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Astrophotography and Sketching >> Beginning and Intermediate Imaging

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gapalp
sage


Reged: 02/16/10

Loc: Georgia
AT65EDQ and triangle stars
      #5001067 - 01/04/12 03:15 PM

There have been some recent posts regarding "pinched optics" and the AT65EDQ:
link1
link2

The stars in my AT65EDQ images look awfully similar. I chalked it up to guiding but now that I re-reviewed these posts, I think I might have the same problem. Any thoughts? I am going to email the vendor about it too.

Image1
Image2
Image3
Image4

One of the suggestions is to "loosen the retaining ring slightly", which fixed a previous users problem. I am not sure what that means though.

Edited by gapalp (01/04/12 03:24 PM)


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LLEEGE
True Blue
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Reged: 03/03/05

Loc: Cloud-chester,NY
Re: AT65EDQ and triangle stars new [Re: gapalp]
      #5001114 - 01/04/12 03:46 PM

The incoming side of the optic has a retaining ring which holds the glass in the cell.
First, extend the dew shield and unscrew it from the sliding ring and set aside. Next, unscrew the outer ring from the lens cell. This is just a ring to protect the threads of the lens cell. Inside, you will see a second retainer ring which holds the optics in place. There are two slots on either side which of this ring which allow the use of a spanner. You should re able to unscrew this with just your finger nails in the slots. Loosen this retainer ring 1/2 turn and re tighten it until it just touches the outer optic. Revers operation to put back together.


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gapalp
sage


Reged: 02/16/10

Loc: Georgia
Re: AT65EDQ and triangle stars new [Re: LLEEGE]
      #5001138 - 01/04/12 04:05 PM

Astronomics says to do it at the focuser end:

"Remove the focuser, unscrew the blue or black ring which has the housing the tight element is in. There is a silver ring with 2 notches in it that you can use a spanner wrench to loosen. Loosen it and then tighten it slightly and everything should be fine."

So which end is it? Plus, where do I get a spanner wrench?

Edited by gapalp (01/04/12 04:10 PM)


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LLEEGE
True Blue
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Reged: 03/03/05

Loc: Cloud-chester,NY
Re: AT65EDQ and triangle stars new [Re: gapalp]
      #5001172 - 01/04/12 04:35 PM

I guess it depends on which element is pinched. As far as where to get a spanner, you can make one or pick one up from a hardware store. I doubt you will need one. I can loosen mine with my fingers. You need to be careful not to slip and scratch the optic with any tools. Finger/fingernail is best.

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mclewis1
Thread Killer
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Reged: 02/25/06

Loc: New Brunswick, Canada
Re: AT65EDQ and triangle stars new [Re: gapalp]
      #5001173 - 01/04/12 04:35 PM

A "spanner" is a generic name for a wrench.

What you are looking for is a pin spanner or pin wrench. There are a number of commercial sources (specialty tool suppliers that will show up on an online search for "pin spanner") for these but you can also make your own from a piece of wood and two nails. You drive the nails in at the same distance as the diameter of the ring you want to move. You then file down the ends of the nails so that they are narrow and squared so that they fit snugly into the little slots on the ring you want to move. If you're careful you can often build a pin spanner that will be an effective tool (no slipping) and will last for years of use.


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kw6562
Authoritative Ignoramus
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Reged: 06/25/08

Loc: MA
Re: AT65EDQ and triangle stars new [Re: gapalp]
      #5001329 - 01/04/12 05:57 PM

Quote:

Astronomics says to do it at the focuser end:

"Remove the focuser, unscrew the blue or black ring which has the housing the tight element is in. There is a silver ring with 2 notches in it that you can use a spanner wrench to loosen. Loosen it and then tighten it slightly and everything should be fine."

So which end is it? Plus, where do I get a spanner wrench?




Astronomics told me the same thing, but I did not see a ring at the focuser side, so I loosened the objective side as LLEEGE mentioned. I used a screwdriver, which is risky, but in my case a fingernail could not provide enough torque to turn the ring. As LLEEGE said, it doesn't take much - just a slight movement to correct the problem.

Please be careful - you might want to send it back to Astronomics if you are not comfortable using tools around the lens. As Mark pointed out, you can make a serviceable pin spanner with a couple of nails and a piece of wood; I've done that in the past for another optical assembly with success. Good luck --Keith


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gapalp
sage


Reged: 02/16/10

Loc: Georgia
Re: AT65EDQ and triangle stars new [Re: kw6562]
      #5001366 - 01/04/12 06:16 PM

Thanks guys. I will loosen the objective side and see what I can do without a tool or with a screwdriver.

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CapnRon
super member


Reged: 03/03/09

Loc: NC
Re: AT65EDQ and triangle stars new [Re: gapalp]
      #5001830 - 01/04/12 11:28 PM Attachment (37 downloads)

I received my AT65EDQ in October and have only had a few outings with it, but I think I may be experiencing the same issue. This is a 30 second exposure, where I paid attention to focus and polar alignment set up, it is a cropped region from an image of M33. The 2 minute exposure of the same region looks nearly identical, but with brighter stars.

I believe I should contact OPT and get their opinion on this, but I thought I would ask here first.

thanks for looking.


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gapalp
sage


Reged: 02/16/10

Loc: Georgia
Re: AT65EDQ and triangle stars new [Re: CapnRon]
      #5002389 - 01/05/12 10:58 AM

Looks like the same problem as mine and the others. I haven't tried the fix yet but will report back when I do.

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gapalp
sage


Reged: 02/16/10

Loc: Georgia
Re: AT65EDQ and triangle stars new [Re: gapalp]
      #5002515 - 01/05/12 12:14 PM

Just got done making the adjustment to the objective retaining ring. I had to use a screwdriver to loosen it since it was so tight. I tightened it back with my hand until it just touched the outer optics. All in all a fairly easy process, just don't let the screwdriver slip!

The next night I get out I will test then post the results. That may be tonight.


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David Ault
sage


Reged: 09/25/10

Loc: Georgetown, TX
Re: AT65EDQ and triangle stars new [Re: gapalp]
      #5003142 - 01/05/12 06:53 PM

After talking with several people about the triangular stars I got with my AT65EDQ I tried loosening the retaining ring on the primary optics first without any improvement. Both OPT and Astronomics thought it was the flattener ring that was too tight and I finally got a good description of how to access it. First, unscrew the focuser assembly from the scope (it just twists off). The flattener is in a separate assembly screwed into the main OTA. Mine was quite tight and took some force to unscrew. Once removed you should be able to loosen the flattener retaining ring just like the one on the primary optics. The retaining ring on my flattener was VERY tight, even when the scope was warm. I had to use a screwdriver to loosen it which also took some force and a lot of care to not touch the optics when it gave way. I must have gone a little too far and unseated the flattener as the ring gave way because I now see potato shaped stars (David B in NM suggested this was the cause).

Good luck with yours.

Regards,
David


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gapalp
sage


Reged: 02/16/10

Loc: Georgia
Re: AT65EDQ and triangle stars new [Re: David Ault]
      #5003243 - 01/05/12 08:16 PM

Thanks for the info. I am seeing the same results with triangle stars even after adjusting the objective side. I see it with 5 and 10 second exposures without autoguiding so I know it is the optics. I will try the focuser side next. If that doesn't work I will have to send it back to the vendor to resolve.

Did you ask the vendor to take yours back since you still have distorted stars?


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David Ault
sage


Reged: 09/25/10

Loc: Georgetown, TX
Re: AT65EDQ and triangle stars new [Re: gapalp]
      #5003357 - 01/05/12 09:49 PM

I purchased the scope from OPT and had actually started a return with them when David B in NM PM'd me and suggested I make sure the flattener was seated properly. I'm just about to test that now. If I get nice round stars I'll ask them to cancel the return tomorrow.

David B in NM just received his AT65EDQ and noticed that his Quality Control card was blank. I went and checked mine and it was blank as well, so you might check yours too.

Regards,
David


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gapalp
sage


Reged: 02/16/10

Loc: Georgia
Re: AT65EDQ and triangle stars new [Re: David Ault]
      #5003486 - 01/05/12 10:54 PM

OK. I adjusted the flattener retaining ring, twice actually. The first time I did it then mounted the scope and did some test images. I was getting potatoe stars instead of triangle stars, similar to David's description.

So I thought it must need tightening some more, maybe I loosened it too much. So I got in there again and tighted it more than hand tighten but not as much as a spanner wrench would (was using a screwdriver) or as much as it was from the factory.

Here are my current results:

10sec
5sec

I believe there is still some distortion, but it is about 90% better than what it was. Do you think I should continue trying to perfect this?


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David B in NM
super member
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Reged: 09/05/10

Re: AT65EDQ and triangle stars new [Re: gapalp]
      #5003494 - 01/05/12 11:00 PM

gapalp,

That looks very good to me even zoomed to 400 percent. Most stars really appear as almost perfect circles through my eyes.

I'd suggest taking a couple real images and see what you think before you make any re-adjustment.

David B in NM


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zerro1
Postmaster
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Reged: 08/02/09

Loc: Smokey Point , 48.12°N 122.25...
Re: AT65EDQ and triangle stars new [Re: gapalp]
      #5003523 - 01/05/12 11:25 PM

it looks like there might still be a small amount. obviously you're on the right track. that flattener is a chunk of glass, isn't it. One thing I did find on mine after quite a bit of use; the 4 screws in the bottom of the focuser mechanism came loose, caused some issues.

I've had mine apart for different reasons but never encountered these distortions that you guy's are experiencing. I had the cell completely dis-assembled and removed the flattener. When I re-assembled, I just "lightly snugged" the retainer ring's. enough to be certain it wouldn't shift but not so much to really put tension on anything.


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gapalp
sage


Reged: 02/16/10

Loc: Georgia
Re: AT65EDQ and triangle stars new [Re: zerro1]
      #5004009 - 01/06/12 10:29 AM

Yeah I notice a small amount of distortion left. I may have a go at another imaging run but if these 5/10 sec exposures are showing, surely longer, stacked images will.

I could make more adjustments to perfect it, but I am at the point of wanting to send it back. It is only a 3 month old scope. If one or two user adjustments doesn't fix it, what is the customer really supposed to do? I am waiting on the opinion of the vendor to see what they say.


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gapalp
sage


Reged: 02/16/10

Loc: Georgia
Re: AT65EDQ and triangle stars new [Re: gapalp]
      #5004052 - 01/06/12 10:59 AM

The vendor (Astronomics) responded feeling the images show I have the element tightened properly. I do trust their opinion in this as they are one of the best vendors I and others have dealt with.

The slight distortions I currently see in these recent images could be from focus/fogging up/ambient temp problems since I had to take the scope inside/outside several times last night while making the adjustments.

I will proceed with an imaging session without any more adjustments. I think I will be satisified with the results. It is a huge improvement over the triangle stars!

Edited by gapalp (01/06/12 11:10 AM)


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David Ault
sage


Reged: 09/25/10

Loc: Georgetown, TX
Re: AT65EDQ and triangle stars new [Re: gapalp]
      #5004363 - 01/06/12 02:38 PM

No ammount of loosening or tightening of retaining rings or attempting to get the flattener seated properly removed my 'potato' stars. Maybe someone more experience than I could correct this, but I decided if it's so fiddly in the first place it's not the right scope for me at this point in time and with my experience. So, mine is going back.

Needless to say I'm a little disappointed, but I can't complain too much. I've gotten a crash course in optics and the overall learning experience should prove invaluable with the rest of my astronomy.

I hope the rest of you come away with more than just education

Regards,
David


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jrcrillyAdministrator
Refractor wienie no more
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Reged: 04/30/03

Loc: NE Ohio
Re: AT65EDQ and triangle stars new [Re: David Ault]
      #5004401 - 01/06/12 03:05 PM

Quote:

I hope the rest of you come away with more than just education

Regards,
David




Me, too. It's really a sweet little imager when working properly (mine required no fiddling).
sample


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gapalp
sage


Reged: 02/16/10

Loc: Georgia
Re: AT65EDQ and triangle stars new [Re: jrcrilly]
      #5004424 - 01/06/12 03:25 PM

Sorry David you couldn't get the results you wanted. Mine could have went either way. I didn't have any experience in this stuff either. Do you plan on exchanging or going with something different?

Jrcrilly, that's about the way my stars look now so your image validates where my optics are at with the adjustments. Thanks for the sample.


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David Ault
sage


Reged: 09/25/10

Loc: Georgetown, TX
Re: AT65EDQ and triangle stars new [Re: gapalp]
      #5004519 - 01/06/12 04:35 PM

I was definitely sorry to see it go. The pictures I had taken with it had lots of potential. I haven't decided on exchanging it for another AT65EDQ or going with something else for wide fields. I think if OPT can confirm that it has been quality checked, or check it themselves before shipping it, I'll consider another one. They guys from OPT were very nice and said I could wait until it arrived (next Wednesday) to decide if I just wanted to return it, exchange it or try something else.

Regards,
David


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CapnRon
super member


Reged: 03/03/09

Loc: NC
Re: AT65EDQ and triangle stars new [Re: David Ault]
      #5004923 - 01/06/12 09:40 PM

I am waiting to hear from OPT as to what they think I should do with mine. They are looking at the pictures I sent them to see what they think the issue is.

thanks for the heads up on this.


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zerro1
Postmaster
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Reged: 08/02/09

Loc: Smokey Point , 48.12°N 122.25...
Re: AT65EDQ and triangle stars new [Re: CapnRon]
      #5005023 - 01/06/12 10:39 PM Attachment (24 downloads)

I really suggest that you guy's give them a shot at getting it straight. These are great little scopes with a nice FOV. If OPT or Astronomics or who ever you got them from can solve this for you, you will still be ahead with this scope. to get anything else that is a quad design with the native flat field it's going to cost much more. If you get another small scope that requires a field flattener to be added to the focuser; now you have extended length and added leverage to cause you other issues like a sagging focus mechanism. I understand the frustration of trying to improve your results, and fighting an optical issue is no fun. You're drawn to the flaw every time you open up photoshop. I've battled issues with the QHY9 and had to ship it to the maufacturer in china no less. I lost some really nice data to the flaw that is now repaired...but now the sky is being completely "un-cooperative", and I may not get anymore shots on the targets I want until next year. It's all a learning experience!

here is an example of data gathered with two different CCD's on the AT65EDQ. One was a QHY8, the other was a QHY9. Sal(SGT500) processed the data from the QHY8 and then I added the QHY9 data to it after the fact.


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CapnRon
super member


Reged: 03/03/09

Loc: NC
Re: AT65EDQ and triangle stars new [Re: zerro1]
      #5009588 - 01/09/12 07:57 PM

OPT has vowed to help me resolve the possible issue with mine. They have first suggested that it might be a associated with focuser sagg and would like me to take a couple of pictures on either side of the meridian. I think this is a reasonable possibility as I have an 8300M SBIG, filterwheel, slim OAG and a Lodestar hanging off the focuser. Although, I only have to back it out about 5/8" to achieve focus. Still I will take the pictures once our skies clear (we need the rain).

I very much want to keep this scope (or its equivelant) because I do like the relatively wide field views it provides and ease of tracking on the CGEM mount.

Happy New Year all,
Ron


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CapnRon
super member


Reged: 03/03/09

Loc: NC
Re: AT65EDQ and triangle stars new [Re: CapnRon]
      #5009611 - 01/09/12 08:19 PM Attachment (19 downloads)

Robert,
I am new at this level of AP and my capture and processing techniques have a long way to go. But I also appreciate the scale of the imaging of this scope.


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David Ault
sage


Reged: 09/25/10

Loc: Georgetown, TX
Re: AT65EDQ and triangle stars new [Re: CapnRon]
      #5009645 - 01/09/12 08:37 PM

Mine was definitely a problem with the scope and not fixable (by me at least). I really liked the scope in all other respects and with everyone's help on Cloudy Nights, I finally decided to ask OPT to exchange it. I also asked them to confirm that the quality control card had been filled out and signed as well as doing an artificial star test before shipping it too me. They were very helpful and willing to work with me, so my replacement scope should be shipping out later in the week after they receive the defective one.

I'm keeping my fingers crossed that there are no problems with this one by the time it gets to me.

Thanks,
David


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zerro1
Postmaster
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Reged: 08/02/09

Loc: Smokey Point , 48.12°N 122.25...
Re: AT65EDQ and triangle stars new [Re: CapnRon]
      #5009909 - 01/09/12 11:39 PM

Quote:

Robert,
I am new at this level of AP and my capture and processing techniques have a long way to go. But I also appreciate the scale of the imaging of this scope.




I spent pretty much the last 2 years expending most my effort on data collection. I figured if I didn't have that part figured out, I wouln't have anything worth processing anyway. So now I struggle with processing. If it wasn't for Sal, Tonk, and Jerry, wouldn't have what few processing skills I do have.

You're ahead of me working with Mono/filter imaging. I'll be on OSC and DSLR for some time to come


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CapnRon
super member


Reged: 03/03/09

Loc: NC
Re: AT65EDQ and triangle stars new [Re: zerro1]
      #5011587 - 01/11/12 12:16 AM

Robert,
I have a long list of people to thank here also, but I have not kept track of their names! Originally I was planning on going the DSLR route, what not to like about using one camera body for multiple tasks. What scared me off was the size of the image files and the concern about storing, manipulating and processing all that data. I figured the mono data was more manigable and you could bin the sensor when you needed to. And I have to admit the purist in me said that mono data with filters was the historical approach. I also have to thank people for steering me into a starting with a short focal length scope. The C9.25 I originally purchased collects a lot of light and looks impressive, but I would be still trying to get past 30 second exposures (if that) if I had not purchased the AT65EDQ to work my way slowly into tracking and guiding. I think your signiture line should read "The more I learn, the less I know I know!"


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zerro1
Postmaster
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Reged: 08/02/09

Loc: Smokey Point , 48.12°N 122.25...
Re: AT65EDQ and triangle stars new [Re: CapnRon]
      #5011600 - 01/11/12 12:28 AM

I know

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CapnRon
super member


Reged: 03/03/09

Loc: NC
Re: AT65EDQ and triangle stars new [Re: zerro1]
      #5021650 - 01/16/12 08:43 PM Attachment (15 downloads)

Why I don't think it is focuser sagg on the AT65EDQ.
First, my camera arrangement is pretty tight and is held well by the focuser. The SBIG is threaded directly to the filter wheel, the OAG mounts on the filter wheel, there is 25mm long adapter on the OAG that is held by a centering Bader ClickLock adapter. The ClickLock has an almost 2" long extension barrel that slides into the focuser and is clamped by two screws on opposing compression rings. All of the screws on the focuser are tight and I don't sense any motion of the cameras by hand.


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CapnRon
super member


Reged: 03/03/09

Loc: NC
Re: AT65EDQ and triangle stars new [Re: CapnRon]
      #5021663 - 01/16/12 08:51 PM Attachment (18 downloads)

The above picture was taken with the cameras mounted on my C5, but the arrangement is the same on the AT65EDQ.

Second. I took images East and West of the Meridian, as suggested by OPT (their resident imagers). I imaged Bellatrix, Menkar and Menkib on the evening of the 12th. Bellatrix was at Alt 140 deg from my location, Menkar was at 220 deg. Menkib was also West of the Meridian but nearly at my Zenith. I imaged at exposures up to 20 seconds without tracking or guiding (all exposures look similar, just some better than others naturally). Here is what the raw data (Dark Subtracted) looks like for the three fields (note: I cropped similar magnitude stars from each field) for the 10 second exposures.


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CapnRon
super member


Reged: 03/03/09

Loc: NC
Re: AT65EDQ and triangle stars new [Re: CapnRon]
      #5021672 - 01/16/12 08:57 PM

All three images produce the same shape (as far as I can tell) even though the cameras were in three different orientations; for Bellatrix it was lying on its right side, for Menkar it was lying on its left side and for Menkib it was lying almost on its back. So, if I have this right in my mind (and that is always a question at my age). It seems that it is something locked into the imaging train that is producing this effect and not somthing that is shifting as the scope moves around.

I have sent this off to OPT and they are looking at the raw data on DropBox, to make their own determination.

Any comments or suggestions here are welcome, I will wait and see where this goes from here.

Ron


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zerro1
Postmaster
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Reged: 08/02/09

Loc: Smokey Point , 48.12°N 122.25...
Re: AT65EDQ and triangle stars new [Re: CapnRon]
      #5021717 - 01/16/12 09:16 PM

Quote:

All three images produce the same shape (as far as I can tell) even though the cameras were in three different orientations; for Bellatrix it was lying on its right side, for Menkar it was lying on its left side and for Menkib it was lying almost on its back. So, if I have this right in my mind (and that is always a question at my age). It seems that it is something locked into the imaging train that is producing this effect and not somthing that is shifting as the scope moves around.

I have sent this off to OPT and they are looking at the raw data on DropBox, to make their own determination.

Any comments or suggestions here are welcome, I will wait and see where this goes from here.

Ron




Hope they get it figured out..

Sent you a PM


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David Ault
sage


Reged: 09/25/10

Loc: Georgetown, TX
Re: AT65EDQ and triangle stars new [Re: zerro1]
      #5024016 - 01/18/12 01:30 AM

Just got my replacement scope today. OPT did an artificial star test before shipping it to me and said it looked good. I did my own test first thing and found the same result so, I was excited to try it out. I did some short exposures on a bright open cluster and found triangle stars again. Feeling disheartened I decided I had nothing to loose by adjusting the retaining rings. This time I had a little more experience and knew that if I let the ring slip to far I'd be back in potato star country, so I very carefully loosened the ring on the primary optics a millimeter at a time until I saw no further improvement. At this point I still had a triangle stars with two points of the triangle almost in line with the star centroid. Now I started on the retaining ring of the flattener and the ends of the triangles slowly got closer to the centroid until I ended up with stars that were as round as I could perceive. The best case test image showed a FWHM of 2.97 and and aspect ratio of 11. So, I am now a happy camper! Now to actually start imaging with it. Thanks everyone for the help and advice.

Thanks,
David


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David Ault
sage


Reged: 09/25/10

Loc: Georgetown, TX
Re: AT65EDQ and triangle stars new [Re: David Ault]
      #5024411 - 01/18/12 10:20 AM

For those that are interested, here's my first real image with the new AT65EDQ:

http://astrobin.com/3795/

In this longer exposure I'm starting to notice some star distortion again. I may loosen the retaining ring of the flattener just a bit more (after waiting until the scope is cold). Even after all the adjustments I made last night the rings are still extremely tight. I just have to be careful and not let anything slip.


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gapalp
sage


Reged: 02/16/10

Loc: Georgia
Re: AT65EDQ and triangle stars new [Re: David Ault]
      #5028984 - 01/20/12 04:15 PM

Stinks a different AT65EDQ needing the same adjustments. Let us know if you make anymore and the results. The stars do look good in the pic but I do see what you are talking about.

I haven't had a chance to image with mine since my testing. Weather and sick babies


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David Ault
sage


Reged: 09/25/10

Loc: Georgetown, TX
Re: AT65EDQ and triangle stars new [Re: gapalp]
      #5029488 - 01/20/12 09:21 PM

I did get some time a couple nights ago to do some actual imaging with the new scope, but I've been busy with work so I haven't had a chance to post. Here are the two images I was able to take:

http://astrobin.com/3875/
http://astrobin.com/3873/

This was after one additional minor adjustment with the retaining ring on the flattener.

Regards,
David


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sullij1
Pooh-Bah


Reged: 11/08/08

Re: AT65EDQ and triangle stars new [Re: David Ault]
      #5029525 - 01/20/12 09:49 PM

Looks like it's all patched up.

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gapalp
sage


Reged: 02/16/10

Loc: Georgia
Re: AT65EDQ and triangle stars new [Re: David Ault]
      #5030502 - 01/21/12 01:39 PM

Yep, looks like you are in business now!

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David Ault
sage


Reged: 09/25/10

Loc: Georgetown, TX
Re: AT65EDQ and triangle stars new [Re: gapalp]
      #5030587 - 01/21/12 02:27 PM

Thanks Guys!

Regards,
David


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BKBrown
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Reged: 08/23/09

Loc: Northern Virginia, USA
Re: AT65EDQ and triangle stars new [Re: gapalp]
      #5614317 - 01/09/13 07:14 PM Attachment (13 downloads)

I recently started imaging with an AT65EDQ I acquired some time ago. It is a sweet scope and provides simple and superb wide field imaging...but I have a problem. The image below is clipped from a series I shot of the Double Cluster last night and it appears to have the dreaded triangular stars that I had not noticed before. Now I am a newbie DSO imager, but it sure looks to me like the issue discussed in this thread. What do folks here think? If it could be something else, I would definitely like to know, if it is the retaining ring thing I am not shy about fixing stuff. Thanks for any thoughts or suggestions!

Clear Skies,
Brian


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David Ault
sage


Reged: 09/25/10

Loc: Georgetown, TX
Re: AT65EDQ and triangle stars new [Re: BKBrown]
      #5614418 - 01/09/13 08:01 PM

Brian,

It's hard to say if this is the same problem. It looks out of focus, was that intentional to highlight the issue? How long is this exposure? I used very short exposures to rule out tracking (5 seconds if I remember correctly).

Once everyone helped me diagnose the issue with mine the fix was quite simple. I had to remove the focuser, then remove the flattener assembly from the back of the OTA (the focuser screws into the flattener assembly which screws into the OTA). Once the flattener assembly is out you can get to the retaining ring on the flattener lens. I loosened mine in very small increments and tested between each change. It took a lot of assembly / disassembly of my rig, but was obviously worth it. I did think it was odd that that it was the flattener lens that was 'pinched' as it is a single lens and not a compound doublet/triplet arrangement, but it did work.

Regards,
David


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BKBrown
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Reged: 08/23/09

Loc: Northern Virginia, USA
Re: AT65EDQ and triangle stars new [Re: David Ault]
      #5614490 - 01/09/13 08:57 PM Attachment (13 downloads)

Thanks David, your info is quite useful. The exposure is 120 seconds at ISO 1600, so it is a long run...and yes it is highly enlarged. Below is the normal version for my reference file.

Clear Skies,
Brian

Edited by BKBrown (01/09/13 09:02 PM)


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Orion58
scholastic sledgehammer


Reged: 10/28/11

Loc: Southern Wisconsin
Re: AT65EDQ and triangle stars new [Re: BKBrown]
      #5615704 - 01/10/13 03:09 PM

As David mentioned, loosen the retaining ring on the flattener and that will probably do it - however, also be very careful not to tighten the actual mounting rings too much when putting the scope back on the mount. The rear ring is directly over the flattener.

The mounting rings fit like a glove but can exert a lot of force on the tube if tightened too much. Once I made both of these adjustments the triangular stars basically disappeared.

Hope this helps.


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