Help Me Decide If I Really Need Another Imaging Scope!

[JayTee]

Hi all,

I'm posing the question of do I really need another imaging telescope.

My current setup uses the ZWO ASI 294MC Pro camera and telescopes that do not cover a focal length gap between 480mm (the f/6 80mm APO) to 960mm (the RC 6 with a .7 reducer). With my sensor, that gap (480-960mm) is "prime real estate" for imaging. Using my sensor specs, I've narrowed down my FL range to 680 - 740mm. That being said I'm now considering the Astro-Tech AT102ED f/7 or the SV Bony SV503 102ED f/7.

I've spent a ton of time on different FOV websites looking at what objects look best in this FL range versus what I currently have. That is how I talked myself into thinking I need a new imaging scope.
So...

1) Do I really need another imaging scope?

2) Does anyone have experience with or an opinion as to which 102 f/7 I should get?

3) If there is a reasonably priced 3rd option, please let me know.

Thank you,

PS, I love new telescopes, umm I actually also love used telescopes!

[Bigzmey]

I would say definite yes! The life is too short we may as well enjoy it. Besides 102mm APO/ED is such a nice size to have even for visual.

I would put Stellarvue doublet or triplet under consideration. I believe Bryan got the triplet and was very happy with it.

https://www.stellarvue.com/

Those are piece of art, premium hand-crafted scopes. But there are also many mass-produced quality scopes in the lower price bracket. The field is very mature and the quality is good for the most known brands.

I have Stellarvue access 102mm doublet which I am very happy with and you could find those used. But I am only using it for visual.

[chris_g]

Hi all,

I'm posing the question of do I really need another imaging telescope.

My current setup uses the ZWO ASI 294MC Pro camera and telescopes that do not cover a focal length gap between 480mm (the f/6 80mm APO) to 960mm (the RC 6 with a .7 reducer). With my sensor, that gap (480-960mm) is "prime real estate" for imaging. Using my sensor specs, I've narrowed down my FL range to 680 - 740mm. That being said I'm now considering the Astro-Tech AT102ED f/7 or the SV Bony SV503 102ED f/7.

I've spent a ton of time on different FOV websites looking at what objects look best in this FL range versus what I currently have. That is how I talked myself into thinking I need a new imaging scope.
So...

1) Do I really need another imaging scope?

2) Does anyone have experience with or an opinion as to which 102 f/7 I should get?

3) If there is a reasonably priced 3rd option, please let me know.

Thank you,

PS, I love new telescopes, umm I actually also love used telescopes!

Option 1, How important is it to you to shoot at that focal length? I am in pretty much the same place as far as focal length; my gap is 600 to about 1300. I'll be getting one around 900mm, the EvoStar ED120 F/7.5 fits the bill quite nicely. And with a reducer, it might do the same for you, you're going to need a flattener anyway. I am hoping that SVBony will put one out at that focal range when I'm ready to buy.

Option 2, While I have no experience with their telescopes, I do have two of their cameras, the quality is nice and inexpensive. I also speced out one their smaller light weight refractors, the 501P for another project, it seemed to be good quality and I decided to get it if I go down that road.

Option 3. I don't think you'll find a more inexpensive option that's new.

Clear Skies,
Chris

[sdbodin]

I really don't see that as a gap. My 480 to 2500 is a gap, but have not seen any reason to fill it. I have been having great pleasure with the short fl's.

So my choice is 135 to 250, a Rokinon or a RedCat.

Two cents, worth every penny,
Steve

[Juno16]

I really don't see that as a gap. My 480 to 2500 is a gap, but have not seen any reason to fill it. I have been having great pleasure with the short fl's.

So my choice is 135 to 250, a Rokinon or a RedCat.

Two cents, worth every penny,
Steve

Completely agree. It’s really enjoyable shooting at low focal lengths.

[Juno16]

Hey JT,

I’ll just throw this in for what it’s worth.
I really like my Explore Scientific ED102. With 0.8 FR/FF, it’s at 571mm.
I’ve got the base model (FDC1, aluminum, 2” focuser), but it has worked well for me.
I got it in 2018 for $879 on sale from ES. Highpoint Scientific has “silver series” (refurbished) models available from time to time and a nice discount.
The only weak point that I’ve found is the 2” focuser.
I took the focuser apart and tuned it and it performs very well especially with the EAF. The focuser should work ok with your 294 sensor.
I’ve really enjoyed using this scope, but like Steve said, I love using the small refractor reduced to 275mm!

[JayTee]

So my choice is 135 to 250

I appreciate and agree with your advice Steve. With traditional camera lenses, I have 18mm to 350mm covered. I believe I have the lower FLs adequately represented.

I really like my Explore Scientific ED102. With 0.8 FR/FF, it’s at 571mm.
I’ve got the base model (FDC1, aluminum, 2” focuser), but it has worked well for me.
I got it in 2018 for $879 on sale from ES. Highpoint Scientific has “silver series” (refurbished) models available from time to time and a nice discount.

This is exactly the spot I'm talking about and for less than a grand. These were precisely the reasons for thinking I need a new imaging scope!

[Bigzmey]

I had a couple of ES APO scopes, 102mm and 127mm. Loved the optics but the focusers were the weak spot.

I feel that Astrotech are better built, and both doublets and triplets are priced attractively.

https://www.astronomics.com/telescopes. ... series=890

Although, they don't offer triplet in 102mm size.

https://www.astronomics.com/telescopes. ... series=889

[JayTee]

I think an f/7 ED doublet should work just fine. It will be used for medium-sized DSOs, which traditionally are not very bright and CA should not be an issue.

I'm leaning even more heavily toward that new scope. I think now it's just a matter of when to pull the trigger.

What originally started me down this path is that my bank told me that I had $900 of reward points that I could take as Amazon gift cards! Whoa who knew! $900! So it's kinda like a free scope???

[Juno16]

I think an f/7 ED doublet should work just fine. It will be used for medium-sized DSOs, which traditionally are not very bright and CA should not be an issue.

Got you there. With a doublet, the DSO’s won’t be an issue with CA, but the brighter stars can be and that is uuuuugly!!!

Sure, you can do some corrections in post processing, but it is only a compromise and a pain in the butt when there are 30 stars with CA to deal with!

As you know, star quality can make or break an image.

[Bigzmey]

I think an f/7 ED doublet should work just fine. It will be used for medium-sized DSOs, which traditionally are not very bright and CA should not be an issue.

Got you there. With a doublet, the DSO’s won’t be an issue with CA, but the brighter stars can be and that is uuuuugly!!!

Sure, you can do some corrections in post processing, but it is only a compromise and a pain in the butt when there are 30 stars with CA to deal with!

As you know, star quality can make or break an image.

For visual doublets work just fine but I suspected that for AP triplets are preferred. In this case it is hard to beat the value of ES. My 127mm APO was silver grade. I got it straight through ES store for a very good price. It was a brand new scope for all purposes, fine performer. As Jim indicated the focuser while on the weaker side worked fine after tune up.

[JayTee]

Patience and luck. Two great commodities! I kept searching the classifieds and AM finally had the ES 102 f/7 triplet (non-FCD glass) up for $650. I had to snap it up. So I guess did need another scope.

With an FL of 714mm it should fill my gap nicely.

Using my sensor specs, I've narrowed down my FL range to 680 - 740mm.

.
.
It should be here next week. First light forthcoming.

Cheers,

I took the focuser apart and tuned it and it performs very well, especially with the EAF.

Jim @Juno16, did you follow any kind of guide to help you with this procedure? If so, care to share?

[Bigzmey]

Patience and luck. Two great commodities! I kept searching the classifieds and AM finally had the ES 102 f/7 triplet (non-FCD glass) up for $650. I had to snap it up. So I guess did need another scope.

It should be here next week. First light forthcoming.

Cheers,

I took the focuser apart and tuned it and it performs very well, especially with the EAF.

Jim @Juno16, did you follow any kind of guide to help you with this procedure? If so, care to share?

Congrats! It should serve you well.

[Juno16]

Patience and luck. Two great commodities! I kept searching the classifieds and AM finally had the ES 102 f/7 triplet (non-FCD glass) up for $650. I had to snap it up. So I guess did need another scope.

It should be here next week. First light forthcoming.

Cheers,

I took the focuser apart and tuned it and it performs very well, especially with the EAF.

Jim @Juno16, did you follow any kind of guide to help you with this procedure? If so, care to share?

Congrats! It should serve you well.

Super! Sounds like a great deal! Mine is FDC1 glass and I have had very good success with it.
What glass does it have? I thought that FDC1 was base level?

My focuser was somewhat rough when I received the scope. I contacted ES support and they sent me this.

Rack and Pinion Focuser Adjustments.docx

(633.76 KiB) Downloaded 18 times

I completely disassembled the focuser and greased with fishing reel grease (all that I had at the time) and reassemble and adjusted per the document. Fixed ‘er right up!
When I added the EAF, I took apart the focuser again and cleaned all of the reel grease out with solvent, dried and lightly greased with Superlube. Very smooth operation.

Works great! A bit if backlash (all focusers do), but NINA compensates perfectly (overshoot method).

Keeps us posted with photos and impressions!

[JayTee]

What glass does it have? I thought that FDC1 was base level?

This is possibly older than the FDC1 glass models. The lens bezel says, "Triple Air-Spaced ED Apochromat" with "EMD Coatings". I'm sure it will work just fine. I've not had bad luck with an ES scope yet.

[Juno16]

What glass does it have? I thought that FDC1 was base level?

This is possibly older than the FDC1 glass models. The lens bezel says, "Triple Air-Spaced ED Apochromat" with "EMD Coatings". I'm sure it will work just fine. I've not had bad luck with an ES scope yet.

Gotcha.
Before my time (AP wise anyway). I’m sure it will do very well for you.
I have to use two extension tubes to reach focus with my ASI533. Your scope should have them included.
I have also had excellent performance with a Stellarview 0.8 FR/FF, but you would might be more interested in just a FF to keep the scope fl at 714mm.

[JayTee]

Well, let's see, I have the Hotech 2 SCA flattener, and I have the Astro-Tech AT2FF field flattener and I also have the Astro-Physics CCDT67 focal reducer (telecompressor) and flattener. So I think I've got those covered.

I'm definitely looking forward to this scopes arrival.

[Juno16]

Dang, sounds like you have it covered!
I tried to get the AT fr/ff before the SV, but. After a year on backorder (pre-covid), I gave up.
Sounds like you are ready to go!

[JayTee]

Sounds like you are ready to go!

Yes I am. Could I please have clear skies now... please?

[Juno16]

Sounds like you are ready to go!

Yes I am. Could I please have clear skies now... please?

I wish that I could grant you that wish!

I know that you are itching for a night to get out and try out your new stuff!

I am excited to see some images from Rimrock Observatory!