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QHYCCD and their insane OAG

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#1 Aurneth

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Posted 29 May 2020 - 09:34 PM

Why is the QYHCCD OAG ring system so dumb?

 

I have what should be a fairly common and straight forward setup for a QHYCCD camera owner:
-a QHYCCD camera (the 294C)
-a Sky-Watcher refractor with the 0.85x focal reducer/flattener

 

For whatever reason, the S-W 0.85x FF has M48m threads and a 55 mm backfocus from the back flange. Why it has 55 mm of backfocus on M48m threads when you'll need a step-down adapter of at least 3 mm length to get to M42m meaning you're now over the standard 55 mm flange-to-sensor distance of most of the T2 adapters on the market. It should be 58 mm on the M48 threads with a 3 mm M48 extender and a 3 mm M48-M42 step-down ring. But I digress as this is about QHYCCD's insanity, not Sky-Watcher's.

 

The 294C, out of the box, has some odd flange adapter of its own that receives M42m threads as well as a 2" to M42m adapter with M48f threads on the upstream side. I say "odd" because the adapter can't actually hold onto a 2" lens cap on its own, nor does it have one specially adapted to it.

 

P1030103.JPG

 

That means it has to be attached to the 2" adapter to retain a dust cap, and naturally this configuration doesn't sit in the original styrofoam cut out in its box. So I had to recut that.

 

P1030105.JPG

P1030104.JPG

 

Also oddly, the 294C's sensor is not in the centre of the optical path - it's offset by 1 mm (it's 10 mm in from one side of the M42f threads and 12 mm in from the other side when it should be about 11 mm from both sides). That starts to explain why the vignetting patterns are never symmetrical in my flats.

 

P1030100.JPG

 

With its flange adapter, the 294C purportedly uses 17 mm of focus. The 2" adapter is 32.5 mm long, so combined they come out to 49.5 mm.

Why? Why make the 2" adapter and/or the flange back a combined 5.5 mm short of what would be a useful out-of-the box length, given that focal reducers and coma correctors usually have 55 mm back focus?

 

So now I would have to go buy a 5 mm extension ring (either M42 or M48; it doesn't actually matter in this case) to make this pretty basic setup work. And I'd still be out by 0.5 mm.



#2 Aurneth

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Posted 29 May 2020 - 09:37 PM

But the insanity with QHY is just getting started. I bought the 294C used and the person from whom I bought it also had the OAG-S and a set of spacer rings (0.5, 1, 2, 3, 7 mm).

 

I barely even know where to get started in describing the ensuing insanity. But let's start at the camera end.

 

So here, the odd flange adapter that receives M42m threads has to come off and be replaced with an even odder one that provides M42m threads. Why are we reversing the direction of M42 threads? No idea. But to do so I have to position a screwdriver in close proximity to and more-or-less facing the sensor to both remove the tiny screws holding the original flange and install the new backwards one.

P1030106.JPG

 

Oh, hey, and just for fun, the screws are positioned such that their heads strike and get stuck in the M42 threads as they come out. This is a daytime at-a-workbench job, not a nighttime in-the-field job.

 

P1030108.JPG

 

So now we have the reverse M42 flange on.

 

P1030110.JPG

 

And the new reverse M42 flange back also doesn't hold a 2" dust cap.

 

P1030109.JPG



#3 Aurneth

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Posted 29 May 2020 - 09:41 PM

In its most basic guise, the OAG-S consists of the integral prism pickup ring of 10 mm thickness and two 3 mm thickness rings on either side, both M42f, all of which are bolted through with 6 bolts.

 

P1030112.JPG P1030113.JPG

Three spare bolts, just in case.

 

So as dumb as this seems with reversed M42 threads and all, one should be able to screw the OAG-S M42f ring onto the M42m flange of the camera ... except you can't because the 294C body gets in the way. Why doesn't the OAG-S have enough clearance for its own housing? I have no idea.

 

P1030115.JPG

 

But we do have these rings.

 

P1030117.JPG

 

Naturally these rings aren't threaded... oh, no, that would be too straightforward. No, no. They're bolted on too. But since the 3 mm M42f ring is needed to attach this contraption to the camera, it has to come off to be replaced by the other rings, then added back to the end. Clearly the original bolts aren't long enough, and perhaps unsurprisingly at this point the longer ones that came with the rings use a 2 mm hex head rather than a Phillips head. I think my predecessor lost the 2 mm Allen key that likely came with it.

 

P1030118.JPG

 

But the longer bolts are only threaded for about 40% of their length near their tips and since the only ring that is threaded for bolts is the 3 mm M42 ring, it turns out that pretty much all of the spacers have to be added in (could probably skip the 1 mm, 2 mm and 3 mm rings). At any rate, after some measuring, all of the rings are likely needed to allow the guide camera to come to focus anyway. Why not just have a single 13 mm ring (or even 16 mm with the reversed M42 threads) instead of dropping in a bunch of smaller rings? QHYCCD do have a 14 mm ring which my predecessor probably should have bought instead... but he likely didn't know that he needed to.

 

At this point you might be wondering... "why didn't you just look up their website?". Funny thing, I did. And maybe he did too. Because here the QHYCCD website itself is profoundly misleading. It suggests that besides the pair of 3 mm M42 rings that come with the OAG, all that is needed is the single reverse flange adapter (which happens to be 3 mm) for "small sized camera", which is how the 294C is classified. A direct quote: "* The QHY294 used a bigger housing body only and the adapter remain the same of small sized camera." Once you've got the 294 you can understand what is meant by "bigger housing body" but a priori all you know is that it supposedly uses the adapters of all their small size cameras.

 

20191122051127948.jpg

from https://www.qhyccd.c...atid=193&id=114

Here, '56 is the reverse M42 flange, with '85 the original normal orientation M42 flange that was removed. '82 and '83 are the 3 mm M42f rings. So there's no indication that you need anything more than what is supplied with the OAG-S besides the '56 reverse flange.



#4 Aurneth

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Posted 29 May 2020 - 09:44 PM

When I finally get all this on and threaded-in ... the off-axis prism pickup is off on some angle where it will cover a corner of the 294C sensor.

 

P1030130.JPG

 

So despite the rigmarole of bolted-on adapters, no one thought to design it so it actually positioned the pickup properly, because that reversed M42 thread in the train added an extra element of variability.

 

Well it turns out that that reverse M42m flange adapter also has 2 possible positions, so between its 2 positions and the 6 possible positions of its M42f counterpart and the fact that it's reversible, you have 24 different possible positions to test. You would, that is, if you were to try them without looking at the basic problem.

 

Looking at the pattern of screw holes on both the flange (4) and the ring (6), it can be seen that the prism is only going to be in the right place when the two holes that are a quarter the way around the ring from the prism are roughly lined up with the two holes on the minor axis of the sensor.

 

P1030120.JPG

 

To solve this without driving you nuts, you actually have to remove the reverse flange from the camera as well as the 3 mm M42 ring from the OAG-S assembly and thread them together to see how the screw holes line up. You then have to have it such that where a pair of holes in the flange more-or-less line up with a pair of holes in the ring, these two holes in the flange need to be positioned along the short axis of the sensor given the hole layout of the OAG.

 

P1030121.JPG

P1030123.JPG

 

And with that you can get the prism in more-or-less the right place. As I had the 0.5 mm spacer left, it turns out that if I place it loose on the M42m threads of the flange adapter and twist on the assembly, I can get the prism square to the sensor. Like, by dumb luck did it manage to get into the right place at the end.

 

P1030124.JPG

 

That is absolutely idiotic.

 

The obvious way to do this would be to incorporate the ability to rotate the OAG in the image train, and just keep everything else on M42 threads... kind of like everyone else does. But if you are going to have these fixed bolts, then drop the intermediary reverse direction M42 threads and have the bolts extend right back to the camera housing so that the prism is on the long axis of the sensor.

 

Now on the other side of the OAG, I still have 18 mm from the flange of the OAG with its M42f threads to the M48m threads of the S-W field flattener/reducer to make up somehow.

This stuff is so convoluted, confusing and ill-thought-out that I could not recommend that anyone actually get into using QHYCCD's OAG products. I suspect it's why my predecessor sold his stuff to me.


Edited by Aurneth, 29 May 2020 - 09:47 PM.


#5 andysea

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Posted 30 May 2020 - 11:55 AM

I see they are still making cameras with the sensor not centered. I replaced the first 294 that I purchased for that very reason.

Thankfully our local Seattle telescope store took it back. The second one was better but I sold it for other reasons (impossible precise calibration....different topic)

By the way, make sure that the flange is well seated onto the camera body or it will leak light.


Edited by andysea, 30 May 2020 - 11:57 AM.

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#6 Aurneth

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Posted 31 May 2020 - 12:29 PM

I see they are still making cameras with the sensor not centered. I replaced the first 294 that I purchased for that very reason.

Thankfully our local Seattle telescope store took it back. The second one was better but I sold it for other reasons (impossible precise calibration....different topic)

By the way, make sure that the flange is well seated onto the camera body or it will leak light.

Well I don't know about "still" as this is a used camera and I don't know when it was manufactured. My photo above doesn't do the issue justice as it's almost impossible to get a photo directly over the sensor that shows it clearly due to parallax, and with the window and depth to the sensor it's hard even to measure it directly.

 

With the flanges off I measured it again from what are symmetric fixed points like screw holes, cell edges, etc.; I now get about a 1 mm total difference (i.e. from the screw holes it's about 1 mm more to one side of the sensor than to the other side). More precisely, it's actually very very close to 1/32 of an inch, putting it a little under 1 mm or about 0.8 mm, for an offset from centre of 1/64" or about 0.4 mm.

 

I've only ever imaged so far with the default flange - I have on order a 1¼" profile guide camera for use with the OAS - but I can't say I've noticed a light leak per se. I get the amplifier glow issue in the upper right edge that others have posted elsewhere, but that's it. That said, as incomprehensible as the reverse M42 thread design is, the design of the 020056 flange should prevent light leak better than the default flange as its vertical sides come almost right down to the camera housing and it's a tighter fit on the rear cell of the housing. It seems a lot more snug overall.



#7 andysea

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Posted 31 May 2020 - 12:36 PM

You are correct, the light leak that I detected was with the stock flange. There was some debris stuck under it, after I removed it and re-set the flange it was ok.

I believe you regarding the offset sensor. In my first sample it was so easy to see by just looking at it.

 

I'm glad you figured out the OAG.



#8 FlankerOneTwo

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Posted 31 May 2020 - 01:29 PM

That certainly seems somewhat tedious.

The system works quite well for the 247c - the OAG screws to the filter wheel, which screws to the camera rotation/centering ring. Works like a champ. I haven't used the 294c, it seems that the camera dovetail might be a different size on the 294c, as the 247c has a dovetail with a native M54 thread. It appears that there is an M42 centering ring that is compatible with the 294c - it is the QHYCCD M42(F) Center Adjustment Ring (020001). The ring on the 247c adds about 7.5mm to the backfocus, not sure about this one.



#9 Aurneth

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Posted 31 May 2020 - 03:51 PM

Spending more time on QHY's website, I looked at the instruction manual for the OAG:

 

https://www.qhyccd.c...catid=30&id=251

 

So there, as opposed to the graphic I posted earlier, they actually do mention the requirement for the supplemental rings (020086). And they have a nice picture of it coming out as it should, but that's not a guarantee (clearly).

 

I can't actually find part 020001 on the list of camera adapters:

https://www.qhyccd.c...atid=193&id=113

accessed from:

https://www.qhyccd.c...lists&catid=193

 

It does appear in a single QHY document:

https://www.qhyccd.c...accessories.pdf

 

020001.png

 

I can't really understand how that would tie into the rest of what I have, though. It has M42f, so the only thing that would thread into is the 020056 reverse flange. So how does the OAG-S attach to the 020001 adjustment ring? As depicted, it has no bolt holes. On the medium cams adapters page, the corresponding 020002 mates with the stock flange, which is fine when used with the standard 2"-M42m adapter. But the OAG has reversed the thread direction, so we now have two M42f threads facing each other and no M42m-M42m rings. The 020002 is also shown with bolt holes in both images, unlike the solitary image of the 020001. I suppose I could buy it and if it has no holes and threads, drill and tap them myself

 

 

But looking all this over, what it seems is actually needed instead of the 020056 reverse M42 flange adapter is something like 020063, the "small sized camera to M54 adapter (screw mount)":

 

020063.png

 

If you look at this carefully (mentally rotate it 90°), it does exactly what I determined had to be done earlier "You then have to have it such that where a pair of holes in the flange more-or-less line up with a pair of holes in the ring, these two holes in the flange need to be positioned along the short axis of the sensor given the hole layout of the OAG." And it does exactly what I concluded should have been done, as well: "But if you are going to have these fixed bolts, then drop the intermediary reverse direction M42 threads and have the bolts extend right back to the camera housing so that the prism is on the long axis of the sensor."

 

The only problem is that 020063 is for the medium size OAG-M whose bolt holes are 62 mm apart rather than the 54 mm on the OAG-S. So if I had the OAG-M and the 020063, I'd be fine, but there is nothing like the 020063 for the OAG-S. If I had a filter wheel plus the 020063, I'd also be fine even with the OAG-S.

 

It seems they designed their system for using an OAG with a FW but using an OAG-S-only was a bit of an afterthought given a kludge of a solution that doesn't have any guarantee of working.

 

My mind is just going to mush trying to come up with a proper solution for this. The QHY website is such a mess that you have to cross reference from multiple pages and fill in gaps by squinting at line drawings.

 

At this point I'm even contemplating buying a third party filter drawer for placement beyond the OAG-S: I'd drill out 6x3 mm countersunk holes into the leading flange to replace the 020083 of the OAG-S (the material of the drawer is also 3 mm thick, like the 020083). The trailing side has a standard M42m thread so it would be back to being "normal" and with a thickness of 16 mm it would nicely replace all the fine adjustment rings, which could then be deployed more profitably ahead of the OAG-S.



#10 lakeorion

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Posted 31 May 2020 - 05:47 PM

I didn't seem to think putting together my QHY 183M + CFW3S + OAG-S was all that difficult.  It was certainly a daytime on a clean flat table job and took a few tries, but it all went together.


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#11 FlankerOneTwo

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Posted 31 May 2020 - 07:34 PM

Hmm. I think I would be tempted to use a M42 male-to-male adapter to connect the angle adjuster to the OAG. That would make it easier to set the camera at an angle where it is not shadowed by the prism.



#12 YAOG

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Posted 31 May 2020 - 08:29 PM

Interestingly if you read the QHYOAG manual on the QHYCCD website the parts and spacing example shown for the QHY294C camera uses the Medium sized QHYOAG, not the Small OAG. You can tell from the mechanical drawings on the site the Medium OAG is needed to clear the body of the QHY294C camera. 



#13 Aurneth

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Posted 31 May 2020 - 09:49 PM

I didn't seem to think putting together my QHY 183M + CFW3S + OAG-S was all that difficult.  It was certainly a daytime on a clean flat table job and took a few tries, but it all went together.

Having now studied the entire system in detail, I can see why it wouldn't be: none of the filter wheel combinations employ either of parts 020083 (the OAG-S to M42f ring - you probably have this part lying around unused) and 020056 (the M42m to camera flange) which have been the source of my problem.

 

Each of those is fixed to something else that is fixed, so if the threading is off - which it is - there is no ready way to adjust their orientation relative to anything else. All one can do is insert various thickness 42 mm diameter spacers between the two of them until it gets closer to alignment.

 

It's that or start inserting other elements into the chain, like M42 male-male adapters and rotators or custom adapters.

 

And apparently I'm not the only one who has had some amount of frustration with this as someone else actually built his own series of adapters:

 

https://www.cloudyni...or-the-qhy-oag/



#14 Aurneth

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Posted 31 May 2020 - 10:01 PM

Interestingly if you read the QHYOAG manual on the QHYCCD website the parts and spacing example shown for the QHY294C camera uses the Medium sized QHYOAG, not the Small OAG. You can tell from the mechanical drawings on the site the Medium OAG is needed to clear the body of the QHY294C camera. 

Where is that example shown? Here's the "QHYOAG User Guide" and I can't see an explicit example with the QHY294C:

 

https://www.qhyccd.c...catid=30&id=251

 

 

Edit:

 

Were you referring to the 294C page itself?

https://www.qhyccd.c...d=94&id=9&cut=1

 

Because there it does mention only the OAG-M in the connection tables near the bottom of the page. But here's where it gets truly silly: the pictures accompanying those tables depict the OAG-S attached to the 294C, not the OAG-M. And if not silly enough, the first "solution" actually employs the OAG-S and associated bits, but they've gone and called it the OAG-M.

 

So just to recap that insanity alone:

 

Solution '0': uses OAG-S, titled OAG-M, depicted using image of OAG-S

Solution '1': uses OAG-M, titled OAG-M, depicted using image of OAG-S

Solution '2': uses OAG-M, titled OAG-M, depicted using image of OAG-S

 

They get so much stuff wrong it'd be a full time job fixing it all.

 

 

That said, looking at the Medium OAG specs with its 47 mm distance between the optical centreline to its 1¼" guider drawtube, it would indeed clear the QHY294C housing by 2 mm, though it would still need spacing to the camera body to enable a guider to get to focus. But the fact you can buy 020088 (14 mm medium spacer) and 020063 (for attaching medium OAG to small cameras) means it would be a straightforward linkage.

 

As the link in my previous post to the other thread in the forum indicates, it doesn't look like the OAG-S is actually a good choice for anyone given the current suite of adapters.


Edited by Aurneth, 31 May 2020 - 10:22 PM.


#15 YAOG

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Posted 01 June 2020 - 12:03 AM

Where is that example shown? Here's the "QHYOAG User Guide" and I can't see an explicit example with the QHY294C:

 

https://www.qhyccd.c...catid=30&id=251

 

 

Edit:

 

Were you referring to the 294C page itself?

https://www.qhyccd.c...d=94&id=9&cut=1

 

Because there it does mention only the OAG-M in the connection tables near the bottom of the page. But here's where it gets truly silly: the pictures accompanying those tables depict the OAG-S attached to the 294C, not the OAG-M. And if not silly enough, the first "solution" actually employs the OAG-S and associated bits, but they've gone and called it the OAG-M.

 

So just to recap that insanity alone:

 

Solution '0': uses OAG-S, titled OAG-M, depicted using image of OAG-S

Solution '1': uses OAG-M, titled OAG-M, depicted using image of OAG-S

Solution '2': uses OAG-M, titled OAG-M, depicted using image of OAG-S

 

They get so much stuff wrong it'd be a full time job fixing it all.

 

 

That said, looking at the Medium OAG specs with its 47 mm distance between the optical centreline to its 1¼" guider drawtube, it would indeed clear the QHY294C housing by 2 mm, though it would still need spacing to the camera body to enable a guider to get to focus. But the fact you can buy 020088 (14 mm medium spacer) and 020063 (for attaching medium OAG to small cameras) means it would be a straightforward linkage.

 

As the link in my previous post to the other thread in the forum indicates, it doesn't look like the OAG-S is actually a good choice for anyone given the current suite of adapters.

Yes, there are mistakes in the documents and they have been there forever. The point is that if you had read the specs you would have seen the QHY294 really needs a Medium OAG. All of this stuff takes some careful reading of the specs and also some interpretation. If you didn't know the Small OAG would fit 100% to be used as you wanted you should have asked for help. As I read it the Small OAG can be used but IMO it is not optimum. When I was reading the charts for the camera I was buying based on the drawings and tables I understood that I needed a Medium OAG and spacers to make it all fit and focus. Ultimately it worked perfectly though I switched to the ZWO cams for the ASIAIR PRO. Now I will say the ZWO system is better designed in that it is easy to setup for standard stuff where the QHYCCD system is more flexible but the configuration can be confusing due to weak documentation. 



#16 mbarber

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Posted 01 June 2020 - 11:36 AM

I see they are still making cameras with the sensor not centered. I replaced the first 294 that I purchased for that very reason.

Thankfully our local Seattle telescope store took it back. The second one was better but I sold it for other reasons (impossible precise calibration....different topic)

By the way, make sure that the flange is well seated onto the camera body or it will leak light.

Andy.  You must have missed my reply to this issue last year:

 

https://www.cloudyni...ndow/?p=9507033

 

I received your original 294 camera from your dealer and measured the sensor position myself.  The sensor was not misaligned.  It only appeared that way due to a slightly rotated adapter with a rectangular aperture.  Zero effect on the image.

 

Regards,

Michael Barber


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#17 Aurneth

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Posted 01 June 2020 - 11:44 PM

Yes, there are mistakes in the documents and they have been there forever. The point is that if you had read the specs you would have seen the QHY294 really needs a Medium OAG. All of this stuff takes some careful reading of the specs and also some interpretation. If you didn't know the Small OAG would fit 100% to be used as you wanted you should have asked for help. As I read it the Small OAG can be used but IMO it is not optimum. When I was reading the charts for the camera I was buying based on the drawings and tables I understood that I needed a Medium OAG and spacers to make it all fit and focus. Ultimately it worked perfectly though I switched to the ZWO cams for the ASIAIR PRO. Now I will say the ZWO system is better designed in that it is easy to setup for standard stuff where the QHYCCD system is more flexible but the configuration can be confusing due to weak documentation. 

Ok, first of all, you haven't actually pointed to the document that you claimed exists to back up your assertion that the QHY294C needs the medium OAG. I have yet to find any QHY document that backs up your claim. So please provide a link or apologize for accusing me of not having read the specs. I'm not going to let you off the hook for that kind of behaviour. Everything that I can find on the QHY site indicates that the 294 is to be regarded as a "small sized camera".

 

https://www.qhyccd.c...atid=193&id=113

"Small sized cooled Camera QHY183、178、224、290、174 163、294*、550

* The QHY294 used a bigger housing body only and the adapter remain the same of small sized camera."

 

How much more explicit can they get in saying the opposite of what you're claiming they say?

 

Second, I was not the initial purchaser - someone else bought the combo and after a cursory glance at the QHY website assumed it would work without issue.

 

Third, the issue at hand isn't that it doesn't fit - it's just kind of dumb to need a slew of fine adjustment rings to get it to a usable location - it's that when you buy all the stated parts and follow the directives on this page

https://www.qhyccd.c...catid=30&id=251

 

you can end up with this:

 

post-211449-0-80092100-1590806570.jpg

 

Do you actually think this is an acceptable way for OAG to be mounted after following the instructions?



#18 akulapanam

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Posted 02 June 2020 - 01:11 AM

I actually really like my OAG, better than my SX one actually and certainly better than the Celestron one.  

 

I would chalk this one up as needed to spend a lot of time figuring out your system before purchasing.  This is a hobby where 100ths of a mm matter.


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#19 GrandadCast

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Posted 03 June 2020 - 09:04 AM

Got bitten too. My QHY22 says to use the OAGS. There are six holds that do not line up. The OAGS has six screws with 54mm spacing, the camera six holes are 62mm spacing. Also got the 020063 since I use a filter wheel. Six screws taken from the camera current adaptor once removed is used to hold the filter wheel directly to the camera with this adaptor, the depth of the hold on the 060063 is too shallow by about .5mm. So it is not going to work, filter wheel is loose on the camera and no way to get it tighten. 

 

So two issues. One is simply the depth of the adaptor 020063 is not deep enough, right parts just wrong machining. The other is both sides, if I would of read every mechanical drawing that one can hunt and peck on the QHYCCD site, then I could of seen that the OAGS would not fit my camera nor the filter wheel. There is an error on one drawing showing the 026003 directly attached to the small filter wheel, this is not possible, the small filter wheel is 54mm and the adaptor is 62mm spacing.

 

I ordered the OAGS by seeing this on the vendor's site.

 

" The "Small" version of the QHY OAG has a diameter of 54mm, and will only work with M42/0.75 adapters. This means it supports camera models with sensors smaller than APS-C format, which includes the QHY21/22/23, the QHY9, the QHY8/10/12 and any other model that has a sensor size of less than APS-C." - So I ordered the OAGS.The QHY22 six hold pattern is 62mm oops.

 

I used the QHY22 quite some time now and the QHY5L-II and know the QHYCCD site is a bit hard to get correct information over the years. For example to find the if you have the latest driver version for a QHY22, you must down load the file that is call QHY22ASCOM-StarSenseSciLatestEdition.zip. So without knowing the version number is my driver that latest version. Only way for years is to just download it, unzip and look at the file property. The website is getting a bit better organized, but it has its fault.

 

In the end, the camera for years have been flawless for me. The QHY22 is amazing. I just need to get the right OAG (OAGM instead of OAGS) and six shorter screws (Ace Hardware or a fine tooth file would do it in a few minutes).

 

Jess

 



#20 jtrezzo

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Posted 03 June 2020 - 05:14 PM

That's quite an unfortunate combo there. More of a 294 problem than the OAG. I don't know why they put the 294C into the medium case body - that usually houses APS-C and full frame cameras (I'm sure there was some reason or why do it). Their other 4/3 size camera the 163M uses the small housing (which would make the OAG-S easy there too). Yet it still has the same small nosepiece. This would be a very easy solution if you could use the OAG-M and they'd just set it up like a normal medium case size camera.

 

I can see why you'd be frustrated. The OAG is actually a very nice one to use provided you don't have such mismatched parts like this on the 294.


Edited by jtrezzo, 03 June 2020 - 05:21 PM.


#21 YAOG

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Posted 03 June 2020 - 08:36 PM

Ok, first of all, you haven't actually pointed to the document that you claimed exists to back up your assertion that the QHY294C needs the medium OAG. I have yet to find any QHY document that backs up your claim. So please provide a link or apologize for accusing me of not having read the specs. I'm not going to let you off the hook for that kind of behaviour. Everything that I can find on the QHY site indicates that the 294 is to be regarded as a "small sized camera".

 

https://www.qhyccd.c...atid=193&id=113

"Small sized cooled Camera QHY183、178、224、290、174 163、294*、550

* The QHY294 used a bigger housing body only and the adapter remain the same of small sized camera."

 

How much more explicit can they get in saying the opposite of what you're claiming they say?

 

Second, I was not the initial purchaser - someone else bought the combo and after a cursory glance at the QHY website assumed it would work without issue.

 

Third, the issue at hand isn't that it doesn't fit - it's just kind of dumb to need a slew of fine adjustment rings to get it to a usable location - it's that when you buy all the stated parts and follow the directives on this page

https://www.qhyccd.c...catid=30&id=251

 

you can end up with this:

 

post-211449-0-80092100-1590806570.jpg

 

Do you actually think this is an acceptable way for OAG to be mounted after following the instructions?

You already posted it for me from the QHY294 specs page, they give three examples and all are using the OAG-M. Yes there are mistakes in the first example where the parts are all for the OAG-S but take the hint, you need to do your own research and track the parts specs down using the adapter charts and you will see the OAG-M is the best fit for that oddball body camera. As I said previously I looked at the mechanical drawings and determined the QHY OAG-M was the one to use for the QHY294C and it also offered the most long term flexibility for a larger sensor camera.

 

Obviously if you did as I did and tracked down the mechanical drawings and dimensions for all the listed part numbers you will see there are errors just as I said there were and have been for a very long time. This is a small Chinese company full of engineers and people who are not native English speakers. I'm sure the Chinese technical information is better than the English descriptions if you care to follow up in their native language it may all be cleared up for you. As I said I had no problem making sense of the adapters but I went and did my homework so I don;t need to blame someone else for making a mistake that was easily resolved before purchasing. 




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