1.20
#... |
|---|
| Are there any wide field APO refractors available with a crayford style or rack and pinion focuser that has a wider field of view than the Radian Raptor 61 which has a F/L of 275mm? I don’t want to use a camera lens even though that might end up being the best option. Clear Skies! |
0.00
#... |
|---|
| Take a look at the Vixen FL55ss. It's 239mm with reducer (303mm without or with flattener only). Been thinking about this small refractor for my own photography but it is quite pricey and you need both the flattener and reducer to reach 239mm, but the reviews I've seen seems to give it a thumbs up for wide field astrophotography. |
0.00
#...
·
1
like
|
|---|
| Although it is quite expensive, you could pair a small refractor with a Starizona Apex ED .65x reducer. That would get you down closer to 200mm. Or if you were to forgo the crayford/rack and pinion focuser, there is the Askar ACL200 F4 lens. I've been using it for a few months and I like it. It's designed specifically for astrophotography so it has a fine focus ring and a coarse focus ring making focusing easier and more precise than with a standard camera lens. It also has an M48 rear thread and up to about 57mm of back focus so you can easily fit most imaging trains. |
|
0.00
#...
·
1
like
|
|---|
|
Yep, you may end up with camera lens. Like Samyang 135mm f/2... My light setup is with that lens, and ASI178MC. That gives me fov 3.27 by 2.20 degrees, and resolution of 3.81" per pixel. |
3.97
#...
·
1
like
|
|---|
|
It is a very expensive option, but there is the Borg 55FL with 200mm focal length: Borg 55FL F3.6 Astrograph with Rack & Pinion Focuser (optcorp.com) And although it doesn't have an RP focuser, I just got a TPO Widefield, which is a really tiny 40mm diameter f/4.5 giving a focal length of 180mm. It's the same telescope as the Askar FMA180 (just re-branded I think). I haven't had a chance to try it out yet (waiting for a couple adapters), but it is supposedly a triplet objective with a field flattener built in. TPO UltraWide 180 f/4.5 Astrophotography Lens & Guide Scope (optcorp.com) Lots of people love the WO Redcat too (fl 250mm). Mine is really nice quality. |
2.81
#... |
|---|
| Why not a camera with a larger sensor ? or a fullframe dslr ? that will make a wider field also. |
|
1.20
#...
·
1
like
|
|---|
|
Thanks for everyone’s advice. I actually think the raptor would be the best choice for my needs. I want to keep away from camera lens style optical tubes. I thought there might be something out there like the raptor with a wider FOV but the raptor is a triplet with a great focuser and nice mounting rings. Just have to locate one which will be difficult. Clear Skies! I wrote the above before I’ve read all the replies. That Borg looks great! I’ll be paring it with the asi2600. Not full frame, but gives me a nice FOV. thanks all! |
