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First light with my first refractor (another M45)

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22 replies to this topic

#1 psuaero

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Posted 02 January 2020 - 08:11 AM

Here's my first image with my new setup. I bought the scope(s) and new camera over the last month and "received" it for Xmas. Last night was the first chance to get out and image on a spectacularly clear night in the north east. Here's my present and also it's first image. I also ditched the Synscan hand controller and switched over to EQMOD/Stellarium for alignment and control so it was really like a whole new experience last night. I couldn't get the PHD2 guiding to work and didn't want to waste such a nice night messing around with the configuration in the COLD so I just went unguided with the new scope.

 

It's a William Optics Zenithstar 73 (73mm/430mm) with FLAT 73A (1:1 flattener). I also mounted a William Optics 50 guide scope (50mm/200mm) and ZWO ASI120mm-S camera for guiding.

WO Z73 case Sm
 
Here's the Pleiades as promised. What do you think?
Image details:
Date: Jan. 1, 2019
Frames: 209x20s ISO800, 30 darks, 36 flats, 40 bias
Total time: 1 hour 9 mins. 40 secs.
Imaging camera: Canon T2i (unmodded)
Telescope: William Optics ZenithStar 73, 430mm, f/5.9, William Optics FLAT73A 1:1 Flattener
Mount: Orion Sirius EQ-G Computerized GoTo Telescope Mount
Software: Backyard EOS, DSS
 
Now, for the questions.
1. What are these patterns around the stars? Here's zoom/crop from the image above. They almost look like diffraction patterns but they shouldn't be there with a refractor.
diffraction spikes
 
2. I didn't seem to capture any color either. Every M45 image I've seen usually has a bluish tint but I didn't see any color (and I tried to bump the saturation quite a bit).
 
3. How do the stars look (for an unguided image)? I think I have the flattener adjusted to the correct distance for my DSLR. This was my first time adjusting one. I didn't bother with my SCT reducer/flattener.
 
Thanks for looking.
John

 


Edited by psuaero, 02 January 2020 - 08:15 AM.

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#2 pyrasanth

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Posted 02 January 2020 - 09:30 AM

A lot of colour should have been captured. Check that your camera is not set to grey scale. The star patterns are more worrying- pinched optics or baffle tube issues?- you should not be seeing these artefacts. 



#3 sg6

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Posted 02 January 2020 - 09:49 AM

Patterns like that were reported by someone 1 or 2 days back, if an answer was offered maybe you will get the answer.

Initially they appear to be 2 options:

Something is pinching the optics somewhere and they are a little out of shape, however ususlly lens and lens cells are held by 3 screws and you have 4.

 

Next is something is sticking out and into the light path. Again I guess 2 options:

Look at the front of the scope objective and see if the spacers that separate the lens are visible. In your case if that is the problem then it appears there are 4 and all are poking out a little but all the same(ish).

Second is that a baffle ring has moved, slightly doubt that as I would not expect a "nice" symetric and even set of "spikes". Also on my ZS61 the focuser travels well up the OTA and would impact I suspect anything out of place.

 

Would best guess at the lens spacers. And there is not a lot that you can do yourself. It would have to be WO to sort.

 

Unfortunately WO seem prone to this at times. My ZS61 is called a 60 everywhere else, so I suspect that WO either make up the extra "1" just to be wider or they shift everything outwards to gain that 1mm and do not leave sufficent space for the lens spacers so they poke out.

 

My thoughts being the lens and cell were designed as 60mm but WO might use thinner retaining rings and shave off fractions elsewhere, but the lens spacers are in and expecting a 60mm aperture so get into the light path.

 

Expect the ZS73 to be available elsewhere but as a 72mm is a distinct possibility.


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#4 psuaero

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Posted 02 January 2020 - 10:35 AM

pyrasanth: I'm 99% sure it's not set to gray scale but I'll double check. I should have looked for something with a bit of color for a qiuck test last night but M42 is hard to see through the trees of my backyard.

 

sg6 or pyrasanth:

What's the best way to document this issue if it's the scope? Should have take some short duration/high ISO images of bright stars? Maybe slightly defocused, like I was trying to look at alignment/collimation?

 

Contact WO and show them the images? Work with the vendor in CA or directly with William Optics? I just got this scope and would hate to send it back but I also spent a reasonable amount of money and if there is a problem I want to get it taken care of ASAP.


Edited by Uwe Pilz, 14 January 2020 - 12:24 PM.


#5 Gucky

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Posted 02 January 2020 - 02:19 PM

To judge about the colours, you could upload one of your unprocessed pictures. If you took them correctly, the colors should show up even on one frame.

 

As you have a separate flattener you could take some pictures without it. This would show whether the problem is with your scope or the flattener.


Edited by Gucky, 02 January 2020 - 03:13 PM.


#6 psuaero

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Posted 02 January 2020 - 05:00 PM

Ok, I didn't upload a full sub but here's a snipped of the line of stars in M45. I noticed  while looking at other images online, that the outer twostars in the line are very gold compared to the inner three stars. I can see the color just fine in my subs. I took a quick look at my original stack (before any adjustments by me) and I can definitely see the colors. So, clearly I'm such a noob at making these stretching adjustments that I somehow removed the majority of color.

 

Here's my example of a single 20 second ISO 800 exposure:

M45 star colors single Sub
 
So, I conclude that I messed up the color. Now I just have to determine why I'm getting the diffraction type spikes. I'm going to go look closely down both ends of the scope with a bright LED and see if I see anything that doesn't look right. I'll post pics if I find something questionable or worth mentioning.

Edited by psuaero, 02 January 2020 - 05:02 PM.


#7 jay.i

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Posted 02 January 2020 - 06:59 PM

The "iron cross" issue seems well documented for WO scopes (screws intruding into the optical path), though Roland Christen (of Astro-Physics) says those weird spikes are from your DSLR sensor. I have not done enough digging nor do I have the actual scopes and cameras in question to test it. But hopefully this points you in the right direction.



#8 psuaero

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Posted 02 January 2020 - 07:28 PM

The "iron cross" issue seems well documented for WO scopes (screws intruding into the optical path), though Roland Christen (of Astro-Physics) says those weird spikes are from your DSLR sensor. I have not done enough digging nor do I have the actual scopes and cameras in question to test it. But hopefully this points you in the right direction.

I doubt it's from my DSLR. Yes, it's old and it has lots of bad pixels but I've never seen those iron cross spikes in images with my SCT. Here's a closeup looking from the front toward the flattener. I see these two tab like things on the edges. They don't seem like they're protruding too much but I can definitely see them. Does anyone else have a Z73 or Z61 that doesn't have these when they look down the barrel?

 

WO Z73 interior
 
Just to be clear... these are way down inside past the many baffles.

Edited by psuaero, 02 January 2020 - 07:29 PM.


#9 OldManSky

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Posted 02 January 2020 - 08:15 PM

I think you’re off to a good start. And as you can tell, I’m a William Optics fan...

The star issue is likely the lens cell hold down screws. WO tightens them down for shipping, sometimes too much. It’s really simple to remedy, though. Contact WO and they’ll explain it thoroughly...basically you just unscrew the dew shield; you’ll find sets of lens cell screws. Back off the front screw in each set about 1/4 turn, and the issue is solved. And this doesn’t loosen the lens cell or affect collimation.


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#10 psuaero

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Posted 02 January 2020 - 10:57 PM

Thanks OldManSky. I'm in contact with WO right now. They asked for a single uncropped sub. I just sent that off to them a few minutes ago. We'll see what they say once they've had a look.

 

If I understand what you've written then the screws are near the front of the scope under the lip of the dew shield. That's definitely not those tab-like things I can see much farther down the optical path (shown in pic above).

 

John



#11 psuaero

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Posted 03 January 2020 - 09:47 AM

Overnight update:

WO reviewed the uncropped sub. They said they "think the collimation screws are too tight" and asked me "to work with the US retailer where I purchased it". WO said they may "adjust the lens or send it back to WO for replacement". Looks like I'm out of the game for a week or two while this gets sorted. It's a shame but I definitely want it made right or replaced. Other than that it's a beautiful scope and the 10:1 RP focuser is a work of art. So much better than the NexStar 6SE focuser.

 

John


Edited by psuaero, 03 January 2020 - 09:48 AM.

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#12 OldManSky

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Posted 03 January 2020 - 07:53 PM

Thanks OldManSky. I'm in contact with WO right now. They asked for a single uncropped sub. I just sent that off to them a few minutes ago. We'll see what they say once they've had a look.

 

If I understand what you've written then the screws are near the front of the scope under the lip of the dew shield. That's definitely not those tab-like things I can see much farther down the optical path (shown in pic above).

 

John

Adding this after your response from WO...

You are correct about the position of the screws. If you’re a little adventurous, you can take care of this yourself, but I understand if you don’t want to. It’s really simple, you won’t harm anything, and you won’t void your warranty. If you want to give it a shot, let me know and I’ll post some photos and directions.



#13 psuaero

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Posted 04 January 2020 - 03:05 PM

Thanks OldManSky. At this point I'm not ready to do it myself. Let's see what the retailer has to say and what they're planning to do. 



#14 psuaero

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Posted 04 January 2020 - 04:22 PM

I provided a friend the raw stacked image and he was able to produce a much better result. I guess I need more practice in the post-processing as well as maybe waiting until the next day so I'm not so tired.

 

Anyway, here's the new version.

M45 209x20s ISO800 1h9m40s V4 annotated

 


Edited by psuaero, 04 January 2020 - 04:31 PM.


#15 psuaero

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Posted 07 January 2020 - 07:42 AM

Update: The retailer asked for me for a defocused star shot yesterday. Luckily, last night was clear and I took a few last night and sent them off. The problem is that they look good to me, really good. I don't the see the iron cross issue. Does anyone think it should show up or not with defocused stars? Have a look. Here is a snippet of the same star field both in focus and out of focus.

 

stars In focus
stars Out Of focus
 
The other day while trying to understand this issue I also did a star test in my basement. I used a piece of aluminum foil with very small holes in it. I put a LED light behind it and shot some images from across the room. I was using this method for collimating my SCT a while back and thought it might show the "iron cross" issue with the refractor. This is what I was seeing with the refractor. No evidence of the "iron cross" that I see in my subs of bright stars. Here's a snippet of my "fake" stars in my basement. I haven't sent this to the retailer or WO for review because I wasn't sure if my setup and fake stars were a valid method of showing an issue or not.
 
Here's an example:
fake stars defocused

 


Edited by psuaero, 07 January 2020 - 10:47 AM.


#16 psuaero

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Posted 09 January 2020 - 03:49 PM

Update: The retailer looked at the defocused star image and asked for three more. The tech wanted to see a de-focused image on both sides (in/out) of focus and also with and without the FLAT73a. Last night was clear and cold (and a windy) but I got everything out and took some images. I could see the issue in three of the four shots of Rigel. I also sent him a control image in sharp focus and both those show the issues. I think this rules out the FLAT73A.

diffraction issues

Waiting to hear back from the tech now.

John


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#17 psuaero

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Posted 13 January 2020 - 06:42 PM

Update: So after a long and very slow back and forth with the tech guy they sent me a RMA for the scope today. They didn't ask me to take off the dew shield and loosen any screws. They didn't even ask if I wanted to exchange. I really do like the scope and will definitely get another of the same model but I'm not buying from the same place. I just didn't think they really cared to help me address the problem and were slow in responding. A simple 30-60 seconds to review images sent via email and then respond shouldn't come with 36 hour turn around time. I understand that everyone is busy and hardware takes time to go over but this was just an image review.



#18 SHFT

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Posted 21 January 2020 - 04:22 PM

Sometimes an RMA is the best option, I don't mind a little tinkering but we should always get a decent amount of quality control.

 

On another topic John, I noticed you own the the same guidescope combo I recently purchased.

Where did you find focus? I tried for 2 nights in a row wihout succes. It seems the 120mm-s is fully in the guidescope?



#19 psuaero

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Posted 21 January 2020 - 08:19 PM

I'm waiting to see if they give me a full refund or try to charge me for "damage". There were some small marks on the dovetail from clamping it into my mount a half dozen times. The rest of the scope was pristine. Those marks couldn't have been avoided with the type of clamp on my Orion Sirius mount.

 

I did have a pretty hard time focusing also. I focused inside one night at about 30 feet. I focused outside under the stars and it took about 30 minutes. I just used the looping view in PHD2 and kept going until I started to see the defocused stars. I did feel like I needed three hands because turning the focuser while holding the ZWO ASI120 in the same orientation was tricky. In my situation there wasn't enough physical clearance to allow the camera USB plug to spin around 360 degrees. I loosened the camera in the Roto-Lock and then held the camera in place while moving the focuser with the other hand. I have it 99% where I want it and might go back for a second round of focusing after I get back from my current business trip. I'll check the focus position on Thursday night or Friday and report back where I have it set.

 

John



#20 IC1101

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Posted Yesterday, 10:29 AM

I am having the same issue with my new Z61. Just processed some images of M42 yesterday and got the identical spikes that you did. Guess I'll be contacting WO to see what they could do. I'd be ok trying to fix it myself if they gave me the option and advice on how to do it.

 

Diffraction Artifact


#21 psuaero

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Posted Yesterday, 10:36 AM

Yes, that's the same issue. I ended up sending it back to the US vendor for a full refund. I received my new WO73 Monday of this week (different vendor) but of course I was out of town on business until last night. Tuesday and Wednesday nights were perfect (well, a bit cold) and clear and my new scope just sat in a box. I'm crossing my fingers that I don't have the issue again. My vendor claimed to be working with WO on what to do but they never asked me to tweak any screws. Just to return it.

 

Good luck. Definitely post up here if you do the fix suggested earlier in this thread. I'll be posting my first light pic as soon as I can get one. Weather isn't looking good in the NE for the next 10 days. Slight chance of partially clear skies tomorrow night so if that happens I'll probably try to grab a few images.


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#22 Heywood

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Posted Yesterday, 04:32 PM

I am having the same issue with my new Z61. Just processed some images of M42 yesterday and got the identical spikes that you did. Guess I'll be contacting WO to see what they could do. I'd be ok trying to fix it myself if they gave me the option and advice on how to do it.

 

 

Are the artifacts in question visible when observing with the eye, or are they visible only in photographs?

 

Thank you!

 

Heywood



#23 psuaero

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Posted Yesterday, 04:50 PM

For me they were only visible in the brighter stars of my images. I definitely couldn't see anything when visually observing. I could see them when properly focused and also when de-focused.




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