110 replies to this topic

[charles.tremblay.darveau]

Finally got a few hours to test the scope with my 2600mm (2 hours within the last 40days ... talk about new scope weather...). I'm very pleased with the results. I have a small amount of tilt, but it doesn't bother me too much and I haven't really got the time to tune it out. Enough data to know it's not going back to the vendor .

 

Single 60sec using the red filter

 

Will report more on the rest of the collected data when I have time to process.

[PeterWar]

Finally got a few hours to test the scope with my 2600mm (2 hours within the last 40days ... talk about new scope weather...). I'm very pleased with the results. I have a small amount of tilt, but it doesn't bother me too much and I haven't really got the time to tune it out. Enough data to know it's not going back to the vendor .

 

Single 60sec using the red filter

spot_diagram_R_60sec_SQA85.jpg

 

Will report more on the rest of the collected data when I have time to process.

Would be nice to get brigter stars in the corner to assess reverse lighthouse effects if present

[charles.tremblay.darveau]

Would be nice to get brigter stars in the corner to assess reverse lighthouse effects if present

It's been TOO cloudy for me to do proper testing of the scope with corner cases (pun intended). Though there is Menkib in the FOV that can be somewhat of a test.

 

Don't see the artefact in the sub.

[GroßATuin]

Hey all together,

received my SQA85 a few days ago. It will be some time until i can test it under clear skies, but i did some testing on an artificial star about 11 m from the telescope. In the star test with an Televue 2xBigBarlow and an 5 mm BaaderHyperion (about 160x magnification) there is no sign of false color or missalignement. All the fresnel rings are symmetric and alligned well. The ronchi shows some pretty obvious undercorrection and a noticable fall of on the edges. See for yourself in the attachement (i could not figure out how to implement the pics into the text)...

I confronted my dealer with the findings. He stated that they have tested some more examples of the SQA85  and all of them showed that fall of on the edges and the undercorrection. Means that this would be inherent of the design.

I am a bit sceptical, especially because of the fall of on the lens edge.

Can anyone confirm this. I am a little bit afraid i got a bad copy?!

No debris found in my copy by the way! The scope was clean and in perfect condition! The mechanical built quality is very impressive!

CS and merry christmas times to you!

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Edited by GroßATuin, 22 December 2024 - 02:35 PM.

[JimTheEngineer]

Cuiv just posted on the Patreon site a review of the SQA85. He had a full frame camera (IMX410) and it clearly shows good stars to the corners and some slight vignetting compared to center (87% in best corner and 81% in worst corner) out of the box - no tilt adjustments. It should be on his YouTube shortly. I really like the scope the more I use it. Stars are tiny. Here is 7hrs on M42 and 10hrs on M45 using an ASI2600MC no filters.

Edited by JimTheEngineer, 24 December 2024 - 01:08 AM.

[JimTheEngineer]

M45

[GeoffC47]

I have a several questions about this promising refractor. 
 

One has been asked: will it work with full frame cameras?  Seems like we need more data on that?

 

A second has to do with maximizing the wide field capabilities to the OTA: do they have a matched reducer that they sell with it?

 

A third has to do with using it for visual; I’d like my refractors to do both AP and visual. The limited travel of the focuser seems like it might rule out visual use. Is that true? Would a Feathertouch or similar focuser resolve any issues and make it usable both for visual and AP? 
 

thanks for any responses - and merry Christmas! 
 

Geoff

[JimTheEngineer]

The new ZWO CAA requires an additional 16.5mm if you want an OAG and filter drawer. The SQA85 only has about 15mm +/- focus travel which means you need a custom part to replace the manual rotator. I did notice the Redcat 91 had 40mm of focuser travel or 20mm +/-. This means the Redcat 91 probably does not require a custom adapter to replace the manual rotator to add the ZWO CAA. Just something to consider with the SQA85.

It's useful to know you can remove the stock rotator, so you can free up precious backfocus space for an electronic rotator. Would good to know from sharpstar/askar what the thread spec is.

Edited by JimTheEngineer, 26 December 2024 - 11:40 PM.

[GroßATuin]

Cuiv just posted on the Patreon site a review of the SQA85. He had a full frame camera (IMX410) and it clearly shows good stars to the corners and some slight vignetting compared to center (87% in best corner and 81% in worst corner) out of the box - no tilt adjustments. It should be on his YouTube shortly. I really like the scope the more I use it. Stars are tiny. Here is 7hrs on M42 and 10hrs on M45 using an ASI2600MC no filters.

This looks promising! Thanks for sharing! I have a experts comment on my ronchi test from an german optics professional. He states, that the undercorrection is probably from the short distance between artificial star and the lense. The fall of on the edges is probably not really a problem for ds photography and if there should be some spherical abberation it should be very minor.
I will get a second copy of the sqa85 and if that one shows a much better result than my first copy, my dealer promised me I might exchange it. But I will definitely try it under some real stars first
Cs

Edited by GroßATuin, 27 December 2024 - 03:43 AM.

[GroßATuin]

I have a several questions about this promising refractor.

One has been asked: will it work with full frame cameras? Seems like we need more data on that?

A second has to do with maximizing the wide field capabilities to the OTA: do they have a matched reducer that they sell with it?

A third has to do with using it for visual; I’d like my refractors to do both AP and visual. The limited travel of the focuser seems like it might rule out visual use. Is that true? Would a Feathertouch or similar focuser resolve any issues and make it usable both for visual and AP?

thanks for any responses - and merry Christmas!

Geoff

Hey Geoff,
no Visual possible with the scope. The fokuser travel and backfokus is to small to get into proper Fokus with the equipment like a diagonal or binoculars. This scope is designed for ap only.
Full frame should be possible. At least looking on the spots. The bigger the pixels, the cleaner the stars probably.
With a 2400 this scope should be a good compromise between light gathering monster and sharpness. Although you would be undersampled quite a bit and should consider drizzle stacking.
Cs Ben

[GeoffC47]

Thanks for that, Ben. 
 

Sharpstar has responded to my inquiry about a possible reducer, “Sorry, there are no such plans at the moment.”

Looks like an AP only OTA, at its current focal length and ratio. Even with that, it looks impressive.

FYI

Geoff

[JimTheEngineer]

Sharpstar probably put this scope out as an 85mm and 106mm to compete directly with the Takahashi FSQ85 and FSQ106. The SQA85 is certainly competitive based on smaller star sizes and much lower price (at least in the US), especially with the more mainstream CMOS cameras sized full frame or less.

Edited by JimTheEngineer, 27 December 2024 - 02:30 PM.

[JimTheEngineer]

Is the thread on the other side an M76x1.0? Does Sharpstar have any M74x1.0 male to M76x1.0 male adapters that are at a minimum length? Say 2-10mm in optical length? I sent in an inquiry to PreciseParts, but the written policy is they do NOT make the part off of drawings, but parts listed. They do not not have the SQA85 listed (or ZWO CAA). Awaiting response from them.

Hello，
The thread of the rotator removed is M74*1

[Apennine]

Is the thread on the other side an M76x1.0? Does Sharpstar have any M74x1.0 male to M76x1.0 male adapters that are at a minimum length? Say 2-10mm in optical length? I sent in an inquiry to PreciseParts, but the written policy is they do NOT make the part off of drawings, but parts listed. They do not not have the SQA85 listed (or ZWO CAA). Awaiting response from them.
 

If Precise Parts has a solution, please let us know. I have a Falcon V2 rotator on mine, but with no OAG. The manual states between 40mm - 70mm of equipment are the limits. I'm going to be re-installing my OAG to work on some guiding issues, but I will not be able to use the electronic rotator anymore (all would be around 80mm), so a solution would be great.

[OliverLXB]

Hi everyone,

I'm seriously considering the SQA85 as it seems to check all the boxes for what I want in a scope of this focal length. However, the OTA is about 20–25mm too long to fit in my photo backpack for carry-on during flights.

From looking at photos and videos, it appears that the dew shield, even when retracted, doesn’t sit completely flush with the front of the OTA.

For those of you who own the SQA85, can you confirm if this is the case? Also, is it possible to completely remove the dew shield to reduce the overall length? If so, how much length would that save?

 

Oliver

 

[Anth]

For those of you who own the SQA85, can you confirm if this is the case? Also, is it possible to completely remove the dew shield to reduce the overall length? If so, how much length would that save?

 

Oliver

Hi Oliver,

 

you should to keep in mind that if you remove the hood, there will be nothing to put the protective cover on and you will have to come up with something to protect the front lens. 
The full length of the OTA is 408mm with the dew guard retracted.

[OliverLXB]

Thanks Anth. I figured I’d have to make a new protective cover, but that should be easy to do.

 

The technical drawing on the Askar website shows indeed the 408mm length.

However, the specifications list the total length as:

403mm(when the dew shield is contracted)
439mm(when the dew shield is stretched)

 

I am curious to know what the total length is with the dew shield removed.

Or could the dew shield be further retracted by removing the tube rings?

[JimTheEngineer]

I don’t really see a way to remove the dew shield. There should be some way to screw it off. Here is a pic of my scope.

Edited by JimTheEngineer, 01 January 2025 - 10:42 AM.

[GroßATuin]

Thanks Anth. I figured I’d have to make a new protective cover, but that should be easy to do.

 

The technical drawing on the Askar website shows indeed the 408mm length.

However, the specifications list the total length as:

403mm(when the dew shield is contracted)
439mm(when the dew shield is stretched)

 

I am curious to know what the total length is with the dew shield removed.

Or could the dew shield be further retracted by removing the tube rings?

Its definitely possible to unscrew the dew shield. The total lenght reduces down to ca. 382 mm.

Also interesting are the collimation screws for the optics.

CS

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[JimTheEngineer]

Was working with Ashley at PreciseParts. The part is now in the Build an Adapter program, but I think it’s untested yet whether this will work with the CAA. I have ordered it in the “0” mm minimum size which takes up only about 1mm backfocus.

In particular there are at least a couple areas to consider. First, the CAA backfocus is 16.5mm and it has a part that extends an additional 18mm towards the scope. So when you install it you have to rack the focuser outward until tightened and then rotate this section to the top to avoid interference with the focuser knobs. Fortunately the SQA85 focuser is 89mm in diameter and the CAA has a clearance of 92mm. However, I think the two top shoes on the focuser need to be removed.

Second, although your OAG backfocus may be 16.5-17.5mm, it’s actually the helical focuser that can interfere with the rotator. I have the Askar M54 OAG which is 17.5mm backspace. There is at least an additional 12.5mm +/- on the camera side of the CAA that is needed to provide the necessary clearance. I have the Agena M54 4-9mm 6 piece set and some fine spacer rings for this adjustment.

The total space available between the 25mm manual rotator and the additional racked in focuser travel of 15mm is 40mm. Based on the above, I should have at least 30mm (16.5+12.5+1.0) of additional parts which leaves 10.0mm for focus and some additional space for clearance between the OAG and CAA (maybe a 2mm gap). So 8mm of focus room is cutting it close.

This is all untested and I hope I haven’t missed anything. Will let you know if this works as soon as I receive the CAA.

Edited by JimTheEngineer, 01 January 2025 - 04:10 PM.

[EdFromNH]

If any of you helpful owners can help with another dew shield question.  The scope diagram on Agena shows the dew shield with an OD of 111mm, but with a front portion of 118 mm OD.  That 118 must be the protective cap based on the other photos (like the one posted above in #65). 

 

Is that black ring at the front with the cap off still 111, or slightly larger? 

 

I'm thinking of getting this scope, but I would like to re-use a motorized flip-flat from another scope.

 

Thank for the info,
Ed

 

[JimTheEngineer]

When I take the lens cover off, I measure 113mm OD on the black surface which looks a bit larger than the dew shield tube. My digital caliper arms are too short to measure the silver tube. If they say it’s 111mm, it looks a little more like maybe 111.5-112.0mm possibly due to what appears to be thicker paint - but maybe it’s right on. The lens cover seems to be 114mm ID with some felt like material on the inside. The OD of the lens cover is 118mm.

Edited by JimTheEngineer, 02 January 2025 - 12:03 AM.

[OliverLXB]

Its definitely possible to unscrew the dew shield. The total lenght reduces down to ca. 382 mm.

Also interesting are the collimation screws for the optics.

CS

Thanks so much! That’s exactly the info I was looking for. The SQA85 is definitely shaping up to be the scope I want to go with.

[EdFromNH]

Thanks Jim!

Ed

When I take the lens cover off, I measure 113mm OD on the black surface which looks a bit larger than the dew shield tube. My digital caliper arms are too short to measure the silver tube. If they say it’s 111mm, it looks a little more like maybe 111.5-112.0mm possibly due to what appears to be thicker paint - but maybe it’s right on. The lens cover seems to be 114mm ID with some felt like material on the inside. The OD of the lens cover is 118mm.

[Raum]

This looks promising! Thanks for sharing! I have a experts comment on my ronchi test from an german optics professional. He states, that the undercorrection is probably from the short distance between artificial star and the lense. The fall of on the edges is probably not really a problem for ds photography and if there should be some spherical abberation it should be very minor.
I will get a second copy of the sqa85 and if that one shows a much better result than my first copy, my dealer promised me I might exchange it. But I will definitely try it under some real stars first
Cs

Hi, I also got mine a couple of weeks ago (too cloudy to image). By the way I tried to screw on my 2inch 28mm eyepiece (it has a 48mm thread in front) directly and have 35mm of focus left. I have always been using newtonians so don't have a diagonal at the moment.

Shouldn't a prismatic diagonal work on it for visual? Would appreciate it if someone could try it.

Edited by Raum, 02 January 2025 - 07:51 PM.