New to photo-astronomy need advice on equipment

[Zapins]

I've always loved looking at pictures of galaxies, stars and the constellations, so I'm curious what kind of setup it would take to get some decent close up pictures of a nebula or galaxy? I'd like it if I could fill up a frame with 1 galaxy at a time and have all the colors show through.

What kind of equipment (and roughly how much $ would it cost)?

I'd like some kind of tracking device too, otherwise I think any long exposure shots would be useless.

I have a gitzo tripod and a canon 5D what else do I need?

[Adrena1in]

I'd like some kind of tracking device too, otherwise I think any long exposure shots would be useless.
Not meaning to sound facetious, but you actually *need* a tracking mount for taking decent photos of galaxies and nebulae. You'll have to track the object acurately for long periods while exposing on the subject. Best to spend a decent part of your budget on a mount...a German Equatorial Mount.

You won't need a particularly big telescope either. 400mm is about right for The Great Andromeda Galaxy, which is apparently huge...spans 3-degrees of sky - the full moon is a mere 0.5-degrees. Some nebulae are also apparently very large - M42, The Orion Nebula, is over 1-degree in size. Good scopes to get you started would be a 66mm to 80mm Apochromatic Refractor, which can cost anything from a few hundred to a few thousand.

I don't have a brilliant mount or an APO though, so I'll let others give you better advice on what to look for.

[Zapins]

Hey, thanks for the quick reply!

A German Equatorial Mount... hmm like a CG-5? What size lens can the CG-5 handle?

I'll be getting a 100-400mm canon lens in the next few days so perhaps I can try taking pics with that? They will no doubt be blurry since I don't have an equatorial mount...

I read something about a 14" SCT being good for nice close ups. I can't find too much info on what this lens is exactly or how much it costs, I'm not familiar with mirrored lenses and their relative power.

I love Nighthound's pictures (post number 21)
http://photography-on-the.net/forum/showthread.php?t=553708&page=2

This is the kind of detail I'm looking for, or as close as I can get to it. What are some options?

[timeasterday]

Yes – a GEM is the way to go. The CG-5 specs I have seen in the past were something like 30 lbs for capacity, but I would never trust that much weight on that mount. For astrophotography you should plan on putting much less weight than the rated specs. Start off with a small refractor in the 300-500mm focal length range, or even a lens in that range. The wide field view is much more forgiving on tracking errors and will help you learn without a bunch of frustration. A 14” SCT would be nice (I would LOVE to have one) but it’s definitely not the way to start off in this hobby, plus they are very expensive. It’s going to be very heavy, requiring a large (i.e. expensive) mount to carry it, and the long focal length of 2000+mm will show any tracking errors and provide a very small FOV.

The CG-5 would be OK to start with, there’s a few tweaks you can do to improve it (well published on the ‘net). A Sirius EQ-G would be even better, but heavier.

[Adrena1in]

I love Nighthound's pictures...

Don't we all!?! ;)

[Nighthound]

Welcome to the astro forum. Great advice and suggestions from Tim & Tim.

Start researching German equatorial mounts within your budget. If you are falling into the range of the CG-5(or the like) then think in terms of the 50 - 400mm focal length range in the optics you choose. If you are serious about staying with this and you have the available budget then I would look at something that will get you more years of use before you find that you need an upgrade to get longer exposure times and less gear error(periodic error). Also, it sounds like you are interested in larger scale in your images and if that's the case the mount you choose(as Tim mentioned) should be one that will handle the heavier scope needed to achieve that as well and the higher quality build to track with precision at those focal lengths. Once you get up to 800mm and above you'll likely want to autoguide which involves using a second scope(on top or next to main imaging scope) with a dedicated guide camera to assist the mount in tracking more accurately. In this hobby higher focal length imaging = more money spent and more patience due to difficulty. There are many deep sky objects that can be imaged nicely at 400mm and widefield shots are stunning, I enjoy looking at multiple objects in one frame and coming from a long focal length beginning in this hobby I've truly come to appreciate lower focal length imaging. With the mount I have I can produce far better results this way and I'm a lot happier in the process.

I have the 100-400L and think it's a great lens, especially for my birding work but it does produce a good bit of false color(most notably as purple/blue halos around stars) due to being under color corrected. It's not an issue at all for terrestrial work but for astro work I'd rate it somewhere between a good achromatic refractor and a very nice doublet semi-APO refractor as far as false color goes. Still I'd definitely use the 100-400 for astro, I especially like it for wide swaths of the Milky Way at 100mm(f/4.5) It's seems to perform best between 100 and 200mm focal length, at least in my experience and the false color is far less noticeable at the lower focal lengths.

Let us know if we can help with the decision making when you look further into your options. If you give us a budget number for your mount we could better suggest some options.

[Zapins]

Thanks for the reply! Lots of good advice in your post! As far as my budget is concerned, I can potentially spend a few thousand on new gear, but as with everyone else, the less the better . I’m glad I will be able to use my 100-400mm lens for some pictures, perhaps I’ll try using an extender for more range? – though I’m not sure how well this works.

I really admire your shots (the ones I saw in the link) and would like to be able to get a picture similar to that (obviously I’ll need loads of practice and luck and probably only get a picture half as good in the end).

As I understand it, the mount seems to be the most important piece of gear. I really don’t know much about the different kinds of mounts and the benefits/drawbacks they have. How does the CG-5 GEM compare with some other mounts? Also are there other things I will need for the mount to use it (things analogous to quick release plates/electronic devices/batteries for the motors/etc…)?

I noticed you have a Losmandy G-11(Gemini). How does this mount compare with the CG-5 GEM? Why did you decide to go with it instead?

You mentioned autoguiding involving 2 scopes. How does one go about setting a system up with two scopes? I assume a second scope will need to be purchased and somehow synced with the first one, does this cost a lot more? If I buy a mount now will I need to get another mount later on with the dual tracking feature or can I just modify any mount to have 2 scopes?

How do mirror lenses compare with regular lenses that have no mirrors for astronomy? Are the qualities different or are there benefits to each? I hear the mirror lenses are quite a lot cheaper should I look into them? Are there any that you would suggest?

Sorry for the millions of questions!

[Zapins]

Just thought of another question :)

What about setups like Meade ETX-90EC Telescope? How do they compare?

[Nighthound]

You're welcome.

To get started I would put autoguiding on the back burner. You'll have plenty of challenges prior to that. Once you've got a good feel for your gear and are progressing with unguided exposures you can then work a guide scope into the mix or use the refractor suggested as a guide scope along with a longer focal length design scope for higher mag/scale imaging.

Here's a brief overview. A guide scope can be mounted directly on top of or side-by-side with your imaging scope. The guide scope would hold your guide camera(web cam, low cost CCD as examples) which would be wired to a laptop and operated with a software guide program and another cable will run to your scope's mount. The guiding software will let you see what the guide scope sees on your laptop. You will select a star on screen and the software will send signals/corrections to your scope mount to keep it from drifting off of that star. This allows for consistent extended exposures without signs of movement, when done properly.

Like I mentioned, that's more advanced and you'll have much to figure out before then like proper alignment and capturing and processing images. There's no quick, easy shortcut to deep sky images. It's technical and it takes a lot of patience but it's extremely rewarding. So take it one step at a time and we'll do our best to help you with the decisions and also with the technical end. It's not rocket science so I certainly don't want to make it sound that way but it's not something that's mastered in a short period of time. Seeing progress is usually enough for most to push them forward to success. It really is great fun to see images of such distant objects appear on your computer monitor that in many cases were not visible(or faintly) through the scope.

My mount(G-11) is a more advanced level mount than most beginners would start out with but those with a bigger budget might invest in one. Losmandy also makes a G-8 which is a smaller mount with less weight capacity utilizing the same Gemini GoTo/tracking system. The G-8 is around $2,600 and the G-11 is $3,100. Not cheap and they are due for a price hike after Jan.1. The Celestron CGE is another mount in the 3K range and is very popular. I didn't start with the G-11 but it was my first choice for a german equatorial(started with a 5" Meade LXD55 refractor and 10" Meade LX200). A friend had a G-11 and I liked his and they're fairly popular with astrophotographers.

Take a look at the Orion Atlas as a beefier alternative to the CG-5 and also the new Celestron mount the CGEM. Both on the $1.400 range. If you were to max out at 3K then this would be proportionate to what you should spend on your mount for imaging purposes. You'll need the rest to get your scope/accesories(i.e dove tail plate for mounting), camera T-ring, dew heater, power sources, etc.

I'm not a fan of mirror camera lenses but if you're referring to mirror telescopes (reflectors) that's a different matter. Newtonians and Schmidt-Cassegrains are excellent but they are much higher focal lengths than I would suggest you start out with. These designs also require knowledge of aligning the optics (collimation) which is no big deal but it does have to be done to keep the scope "tuned" for imaging.

A nice 80-90mm refractor would be an excellent place to start. Try to keep the focal ratio(f number) in the 5 to range for deep sky to help with capturing more light quicker meaning shorter exposures needed in your early stages of learning. You'll also want to pick up a field flattener/reducer to correct the optical curvature that is inherent in refractors.

Much more to cover but for now I would research products. Cloudy Nights forums is chock full of useful info from experienced users. The research will help you get the most bang for your buck and help you avoid unnecessary frustration. And of course we're here to help too.

Edit: I would avoid the ETX scopes and stay with a german equatorial mount for imaging.

[Zapins]

Thanks for your patience and thourough explanations and advice, it is really hard to glean all the information I need off the net on my own and so nice to find it all nicely summarized in a few posts!

Ok, so I won’t worry about autoguiding for the time being except to ask one last question: without autoguiding will long exposures have star trails and streaks or is there some kind of tracking that a GEM is capable of on its own without an autoguiding system?

What are the essential basic parts that I would need to get to start taking pictures? I have a 100-400mm canon lens, and a canon 5D that I am hoping will get me at least part of the way there.

I see I will need a GEM of some kind, and probably an autoguiding system later on, but you mentioned a 80-90mm refractor, dove tail plate, camera T-ring, dew heater, power sources and field flattener/reducer. Are all these pieces of equipment essential or are they pieces that I can look into later on if the astro-bug bites hard? What does a bare bones setup contain that will allow me to take long exposures without streaking stars and that I can add to over time when I have the money without having to sell all my noobie equipment and start over each time?

Sorry for the confusion, I did mean mirror telescopes like the Newtonians/Schmidt-Cassegrains.

I assume there are many kinds of telescopes out there but I figured I’d ask anyway. Are all telescopes suitable for camera use? Or are some specifically made for the human eye and not cameras?

You mentioned that I should stay away from ETX scopes. Why is that? I checked Ebay and it seems pretty fancy – at least to a noobie 

http://cgi.ebay.com/Meade-ETX-90-Astrophotography-Telescope-Kit-Complete_W0QQitemZ150310465262QQcmdZViewItemQQptZT elescopes?hash=item150310465262&_trksid=p3286.c0.m14&_trkparms=72%3A1234|66%3A2|65%3A12|39%3A1|240%3A13 18

I’ll also check out cloudy nights forum.

[FarmerDave8N]

Sorry to jump in on Nighthound, but I have a few free minutes. :)

without autoguiding will long exposures have star trails and streaks or is there some kind of tracking that a GEM is capable of on its own without an autoguiding system?

The whole point of a GEM is that it points to the appropriate celestial pole, and as the earth rotates it tracks at the same apparent speed (i.e., sidereal rate) that celestial bodies do, so it more or less points at the same spot over time - so no streaks/trails. This isn't actually true, as the mount's mechanics will cause it to move up and down (periodic error) and the odds of you pointing the mount *precisely* at the celestial pole are slim. However, at short enough focal lengths, you can take fairly long exposures without being "off" enough for it to show up.

What does a bare bones setup contain that will allow me to take long exposures without streaking stars and that I can add to over time when I have the money without having to sell all my noobie equipment and start over each time?If you want to go *really* bare bones, you can try a barn-door tracker. Otherwise, a GEM, and a dovetail bar, and your camera/lens is a good start.


You mentioned that I should stay away from ETX scopes. Why is that? I checked Ebay and it seems pretty fancy – at least to a noobie 
ETX scopes are on alt/az fork mounts (altitude/azimuth) - meaning they don't track "around" like a GEM. So, you're going to get what's called "field rotation" in your pics - in other words, streaks - and when you stack them, you'll end up with a mess. Look at these samples pages from Michael Covington's book, Digital SLR Astrophotography:

http://www.covingtoninnovations.com/dslr/DslrSamplePages.pdf

Pages 11 and 12 of the samples (pages 100-101 of the actual book) explain the difference in pictures far better than I ever could in words.

HTH,
David

[Nighthound]

You're welcome and no problem at all.

The scope mention was only because I thought you were looking for a scope and mount rig but if you're content for the time being with a mount for your new 100-400 lens/camera then by all means hold off on the telescope(refractor) for now. You might still be thinking about the dew heater/strap for your lens if you live in an area where dew and frost is an issue.

Don't confuse tracking with guiding or auto guiding. Tracking and GoTo pointing is standard in many GEMs. They track in sidereal rate(exact rate at which earth rotates). Guiding is using outside influence such as software/laptop/guide scope/camera to correct your mounts mechanical imperfections in order to reduce or eliminate unwanted drift or movement that will cause star trails or star distortion.

There are other light duty options out there for a camera and lens set up that would work with a small lightweight refractor(60-70mm) down the road as well. The down side would be that you can't place much more on them but they are extremely portable.
This may or may not be a priority depending on whether or not you have to travel to dark skies to image.

The Takahashi Teegul is a nice set up for lens imaging.
http://www.buytelescopes.com/product.asp?m=&pid=1733&display=reviews

Here's an interesting tracker. The AstroTrak TT320X. It mounts on a photo tripod(the heavier duty the better)
http://www.optcorp.com/product.aspx?pid=12026

These above two are just alternatives for consideration. They offer sidereal tracking in compact and lightweight rigs that are very portable. They won't be something you can grow into for larger scopes with longer focal length but they will work with camera and lenses and won't mean putting out a bundle of money before knowing if this is the hobby for you for the long term. just thought I'd mention them.

The ETX line scopes are fork mount scopes that track in altazimuth. The vertical movement of a scope is known as the altitude, while the horizontal motion is referred to as azimuth. The ETX scope have a dual motor drive that tracks objects across the sky by adjusting for both altitude and azimuth along the way. This dual means of tracking causes what is referred to as field rotation. This has a negative effect on astrophotography. The object in the center of the image will be relatively normal while the stars on the outer edge of the frame will appear to be moving in a circular manner due to the rotation effect. This becomes more pronounced as you lengthen the exposure times. By using a GEM you eliminate this dual axis tracking effect since they use a single axis(mainly) to track objects as they move from east to west.

There are devices, called a wedge, that will allow you to track in sidereal with a fork mount but they are additional cost and the low level consumer models are crude at best and make the fine tune adjustments necessary during alignment very frustrating. Much nicer/accurate ones are out there but are expensive and are not made for ETX scopes, at least I don't think there's one out there. It would likely cost more than the scope itself and would be in my opinion the strong link with the scope being the weaker. These scopes just weren't designed for imaging, fine for viewing or for planetary imaging but not for long exposure work. The weight of a DSLR on one of these scopes/mounts is a bit much as well.