refractor, reflector, or cat?

[drevilsmom]

Now that I have a mount that will (hopefully) last a long time, I really am torn as to what to provide as a scope. I've used only Schmidt-Cassegrains (LX200, C-5, and C8 ) at the university that I taught night lab at, so I know what is possible with them. I could find and easily discern the Ring Nebula with the 5". However, knowing there are other possibilities, I was curious as to what would be a good scope. I want one that not only has good visual abilities, but also can be used for AP. My suspicions are that reflectors such as Newtonians would fit this bill, but collimation is something I've never done, although I wouldn't hesitate to learn. It was kept up with at the University for the SC's (I assume, LOL). My opinions on refractors are limited, and what little I have found suggests that they do not have the light gathering ability of a reflector. As for reflectors, some that I have looked at are on Alt-Az mounts, and if you were to place them on a GEM, the eyepiece would be in an awkward place to attach a camera to, am I right? I guess my main issue is that there is a 6" Starblaster f/5 up for sale, and I'm really tempted! :P

[skipper34]

Tell us about your mount and we may be able to give some suggestions for a scope. The rule as for AP with a telescope is that the mount is of paramount importance compared to the scope. The world's finest scope is worthless on a shaky mount.

[Daniel Browning]

Originally Posted by drevilsmom

I want one that not only has good visual abilities, but also can be used for AP.

Under many circumstances the two are directly opposed, so you have to choose what's more important and then make compromises.

For example, if AP is more important, then you get a light-weight telescope and just live with the reduced visual capability. If visual is more important, then you get a heavy telescope and just live with the reduced imaging capability.

[Jeff]

I've heard that the Celestron 9.25 SCT's are a really good compromise between visual and AP. The tube weight seems like it would be ok with the mount you mentioned in your other thread. Something I heard too about the central obstruction being a smaller percentage of the mirror size came into play too. Can't remember the details on that though.

[drevilsmom]

Well, I've got a CG-5GT coming here shortly. I know that it is not top of the line, but I do not have the capabilities to keep it here at the house due to us living in a wooded area. The largest opening allows for about an hour of imaging at best and only towards the south. So.... I have to cart it to the farm less than a mile away. Great skies, but I wanted something that was a little bit more lightweight. I'm pretty sure that this is fairly heavy, as the guy that had it before me put silicone caulk in the legs so it would support his 10" Newt. Jeff, I've thought about the Celestron SCT's. I actually used a couple of different orange tubes while at college, and they were very nice.

[Nighthound]

Elizabeth, keep in mind the mount's capability when choosing focal length, especially if you do not plan to guide using a second scope. As Daniel mentioned above an imaging scope and a visual scope can be two different animals, especially when your mount has limitations like periodic error(without correction feature) as well as weight tolerance. I understand the desire for large aperture in say an SCT for visual but long exposures will be difficult on the CG-5 unguided. Great for visual but a serious challenge for imaging. I would suggest a 80-90mm(f/5ish) refractor with ED glass for imaging with the CG-5. While the smaller aperture will be a compromise for visual, the lighter weight and shorter focal length are a better match for the mount and long exposure work. It can also be moved into a guide scope role down the road. Keep in mind too that there are many objects in the sky for a good portion of the year that will require a wider field scope to image in their entirety. The Rosette, Andromeda, Markarian's Chain, Heart Nebula, The Sword of Orion just to name a few. I've imaged at many different focal lengths over the years but I keep coming back to the 400-500mm range. Partially because it makes precious nights out more enjoyable and productive. I also enjoy images that contain multiple objects, more to look at and I really enjoy large star fields. I'd love to have a 3000mm FL scope for galaxies but I don't see me having a mount capable of handling one for some time, if ever. That's my two pennies, keep us posted on your decision.

[dpastern]

I'd also recommend the refractor route, 4" or so. The Megrez 90 is a nice scope. Solid build, good optics by all accounts, reasonably focal length and FOV, just right for imaging.

Dave

[chris.bailey]

Another vote for a refractor here too. So easy to setup and next to no maintainence. I would also suggest that the general quality of refractors has got better. The MZ90 is a nice scope indeed and good value if you can get a deal now with W/O pulling out of the US.

[Nighthound]

In line cost-wise with the WO Megrez 90(non-sale price) is this ED refractor by Stellarvue. It's VERY nice, my buddy images with this scope and the Feathertouch focuser is a thing of beauty in itself, buttery smooth. The scope build and optics are a great value at this price point. Once you've focused a scope while imaging using a Feathertouch focuser, it's hard to go back to stock focusers. I'd rate the Moonlights at the top as well.

http://www.optcorp.com/product.aspx?...-765-1201-9645

* You'll have to budget for a field flattener/reducer for imaging with a refractor, not a big expense. More than a reducer for an SCT, but not much more. If you chose a Newtonian you'd need a coma corrector.

[drevilsmom]

Yes, the more I looked at images, the more I realized that many people are using refractors. However, in order to purchase ones that you all listed, I'd be saving for a couple of years, and then explaining to my hubby why they cost so much. I realize that the more you pay, the better the optics typically, and that triplets are "typically" better than doubles, but what is a decent one for around $500? I was kind of leaning towards this one.

[Nighthound]

That's a fine scope for the money and one that is very popular.

The Astro-Tech line are very nice and fall within your range as well. The focuser on these scopes will make tweaking a breeze. Having a 10:1 adjustment is VERY useful:
https://www.highpointscientific.com/...idProduct=3398

The Triplet is not that much more, carbon fiber tube and 11:1 fine focus. I've never seen this one before, looks very nice:
https://www.highpointscientific.com/...idProduct=4579

[drevilsmom]

I really like the fine focus. As a lab tech who uses high power with oil on a microscope, I can attest that the fine focus makes my lab life a ton easier. I also think that I recently saw a discussion of the second refractor on CloudyNights.

I may see if I can wait to get a used Astro-Tech triplet on CloudyNights or AstroMart, while going ahead and saving up for a new one in case I don't see one. However, a recent search shows that one comes up every 3-4 months.

[Nighthound]

Originally Posted by drevilsmom

I really like the fine focus. As a lab tech who uses high power with oil on a microscope, I can attest that the fine focus makes my lab life a ton easier. I also think that I recently saw a discussion of the second refractor on CloudyNights.

I may see if I can wait to get a used Astro-Tech triplet on CloudyNights or AstroMart, while going ahead and saving up for a new one in case I don't see one. However, a recent search shows that one comes up every 3-4 months.

Great idea, I've found most people in the hobby take very good care of their scopes. Refractors are sturdy too so that helps. I would suggest having the one you choose sent at least 2nd day air to avoid a rough transit through trucking. The extra 20-30 dollars is well spent. Hope you get one that fits your needs soon. Let us know what you decide.