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PHD - About to give up

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#26 astrodog73

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Posted 03 November 2013 - 04:55 AM

The screen grabs definitely look like hot pixels, but the graphs suggest you are guiding on stars.... hot pixels give really nice graphs....

#27 Madratter

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Posted 03 November 2013 - 07:56 AM

The suggestion to try metaguide is a good one. On top of that, you should be able to focus things in daylight with that camera. Obviously the exposure will be real short.

#28 Wmacky

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Posted 03 November 2013 - 10:16 AM

Its hard to perform diagnosis from a distance, but I'm just don't see a image of stars in your screen captures. Suggest you slew the scope to a very bright star and make sure you can see and focus on it with the guidecam and PHD. So there is no ambiguity about framing, focus and exposure.

If you got is setup right it will be a question of which star to chose as a guide star. Not is there a guide star?


I did do that, and results are the pics of the graphs. I have never seen more than 2 guide stars in a frame, but usually none at all. This is with good focus on what guide stars I can find. I think I have a serious issue with the cam, or the mount, or both. I have no idea what to try next other than metaguide.

Also I'm headed out to test focus the AT6RC in daylight.

I guess next step will be another guide cam. I was thinking about a mono ASI120MM anyway as a part of my planetary arsenal, but now I'm gun shy. Do I really have to have a Lodestar?

Has anyone directly compared the ASI120MC to the ASI120MM for guiding purposes? Is there a big difference?

Thanks for the help guys, I know no astrophotography people locally, or heck, even anyone else that even owns a scope. This is my only resource.

#29 SergeC

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Posted 03 November 2013 - 11:22 AM

I'm not familiar with your guide cam so I can't give advice on the problems you're seeing. About your local resources, Alachua Astronomy Club is reasonably local, as is NEFAS. Both have monthly star parties and active AP-ers as members.

#30 zerro1

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Posted 03 November 2013 - 11:35 AM

I use a Meade DSI pro that I picked up used for $100.00 that worked so well I got a second one for another imaging setup. I have compared it to the SSAG (Orion "Star Shoot Auto Guider") The SSAG is certaily less sensitive than the Meade DSI. I always have plenty of stars to choose from with the Meade. It's not a guider in that it does not have a guide port on the camera.

do try to get guiding sorted out before you try to change mounts. a poor guiding situation would make a mount look like its in sad shape. Once the guiding is solved, it can help pinpoint problems as you learn how to regognize what is coming from the mount

#31 Madratter

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Posted 03 November 2013 - 11:52 AM

Its hard to perform diagnosis from a distance, but I'm just don't see a image of stars in your screen captures. Suggest you slew the scope to a very bright star and make sure you can see and focus on it with the guidecam and PHD. So there is no ambiguity about framing, focus and exposure.

If you got is setup right it will be a question of which star to chose as a guide star. Not is there a guide star?


I did do that, and results are the pics of the graphs. I have never seen more than 2 guide stars in a frame, but usually none at all. This is with good focus on what guide stars I can find. I think I have a serious issue with the cam, or the mount, or both. I have no idea what to try next other than metaguide.

Also I'm headed out to test focus the AT6RC in daylight.

I guess next step will be another guide cam. I was thinking about a mono ASI120MM anyway as a part of my planetary arsenal, but now I'm gun shy. Do I really have to have a Lodestar?

Has anyone directly compared the ASI120MC to the ASI120MM for guiding purposes? Is there a big difference?

Thanks for the help guys, I know no astrophotography people locally, or heck, even anyone else that even owns a scope. This is my only resource.


A couple of things:

1) If you get to the point you consider the lodestar (and I don't really think that will be necessary), also consider the SBIG ST-i mono. It is also quite sensitive and is pretty clean as these guiders go. Don't get the color one for this purpose. I have it. It works, but the mono is clearly better (it is also 100$ more which mattered to me at the time).

2) Trying to learn guiding at the focal lengths you are trying at is bound to cause frustration. Learning on a 50mm guider (which I have successfully used to guide up to 2000mm scopes) is much much easier. The reason has to do with the ease of finding guide stars. It isn't so much the focal length, as the f/ratio. The Orion 50mm guiders are f/3.2. Sure the larger scope pulls in fainter stars. But what counts for this purpose is the signal to noise ratio on the sensor. And because of that the faster the f/ratio of the scope, the more stars in practice you will have to guide with. When I realized that, it was one of the things that steered me away from the ST-80 guide scopes. The advantage of longer focal length is less difference in image scale between the main scope, and the guider. But even the 50mm does fine at 2000mm. And it is easier to secure things with less flex as well. In other words, you chose to make things hard on yourself. Maybe once you were more experienced this would have been a good idea. But certainly not now.

3) Your mount may indeed be bad. But the session last night gives no useful information on that front. Don't be so fast to conclude you need a different mount. You probably could have been using an Astro-Physics Mach1 and still had the problems you were seeing.

#32 CounterWeight

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Posted 03 November 2013 - 12:05 PM

I know I'm late to the party but all those first images appear to be just noise and maybe hot pixels, so there is some issue with the signal. White after dark cal shows a huge imbalance between expected and actual, so IMO all bets off until you get that completely sorted. IMO that points to the driver for the camera and the software looking with it and how. Hope the Metaguide software helps!

BTW, I can't seem to find those in the supported cameras list, is it there and I just don't see it? also don't see a direct statement that it's PHD compliant at least on the OPT site or the ZWO site. Anyway with the Orion SSAG they include PHD, at least with those I've bought - any chance there was a version on the install disk?

That you get better images unguided is great in ways as shows the mount tracking is good/decent from your polar alignment alone. I wouldn't worry about the mount based on what is happening here with this guide camera issue.

#33 Dwight J

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Posted 03 November 2013 - 12:30 PM

As mentioned already, using a 6" F9 scope, even with a reducer, is way too long a focal length to guide with initially. The field of view, especially with tiny chipped guide cameras, is very small making it highly unlikely a suitable guide star will appear. You will need to inset an eyepiece and use the screws in the guidesscope rings to center a suitably bright star, then reinsert the camera and focus it. Use of a par focal ring will simplify this operation in the future.

#34 Wmacky

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Posted 03 November 2013 - 06:45 PM

Thanks for those comments.

As to guiding with the AT6RC. Yes, I know it's not the best way to begin, but with reports of people finding lots of guide stars with the newer sensitive cameras, even with OAGs on SCTs, gave me hope. Perhaps, this isn't as true as I had read?


I had never used the AT6RC before so today I test focused it in daylight, and it focused ok. With the ASI the view was kinda soft, and washed out. Not a very impressive view. Same with it in the EON 80, but no real problems found. However, as others have stated, the FOV (even with a FC) was indeed tiny. Focusing on my neighbors fence about 200' away showed a single nail head surrounded by a small amount of wood! I'm starting to think that those who reported plentiful stars with this MC version cam were using a Mini guider. :question:

What next?

Well, I guess I could wait, and try Metaguide next weekend if it'd clear. (weekends only for me).

Or I could purchase a better mono cam, or a 50mm Mini guider, or perhaps both?

I can't really think of anything else to try. I feel that waiting and just trying to adjust PHD setting numbers will waste out another good weekend.

I'd still love to hear from someone that has atempted to guide with the ASI120MC at a longer FL. (> 1000mm)

#35 Raginar

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Posted 03 November 2013 - 06:56 PM

Seems a little excessive. You didn't even try meta guide. A finder guider would probably be a better bet than using your RC though.

#36 Wmacky

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Posted 03 November 2013 - 07:18 PM

Seems a little excessive. You didn't even try meta guide. A finder guider would probably be a better bet than using your RC though.


Probably right. It's just in Florida we are afforded a small imaging season of just a few precious dry months. I sure hate to waste the good cloud free ones! :grin:

#37 frozen.kryo

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Posted 03 November 2013 - 08:57 PM

Have you tried using the ascom chooser to select the guide camera? (instead of using wdm?)

#38 Raginar

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Posted 03 November 2013 - 10:06 PM

Well, if your budget allows, get the lodestar/mini-guider. You won't be disappointed. It was the best purchase I made when I upgraded from a SSAG.

The lodestar is such a beast!

#39 astrodog73

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Posted 04 November 2013 - 03:53 AM

+1 for lodestar... I guide with one, I'm tossing up getting another to image with... A friend guided on a galactic core once with his lodestar.

I would also pick up a cheap, fast, short achromat, and use that instead of the RC.... I've never heard of anyone using an RC as a guide scope (might be a reason behind that??) :)

#40 Wmacky

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Posted 04 November 2013 - 09:01 AM

Good news first - I was able to order an adapter for one of my 50mm finders, So I'll have a new guide scope for $29.


Tha bad. Wow, the lodestar is more expensive than remebered! Thats a big expense with IDAS filters still to purchase, a light box supplies needed. Any less expensive options for a sensitive cam? I was thinking about purchasing a ASI120MM for plantetary work anyway, but there's not much info on these being used for guiding, and it's bad to be a trail blazer when a newbie! Especially, after using the MC version with no real guidance available from other users with that cam.

#41 Jeff2011

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Posted 04 November 2013 - 09:17 AM

Wmacky,

Have you thought about the QHY5L-II mono? It has the same chip as the ASI120MM. I have no problems using mine as a guide camera and connect with PHD using the ASCOM drivers that are available from the QHY web site.

Here is a link to a retailer that sells them in the US.
https://www.astrofac...5l-ii-mono.html

#42 CounterWeight

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Posted 04 November 2013 - 09:29 AM

Can you return the one you have and recoup some cost? My thought is 'why do you NEED such sensitive guiding just starting out?', you really don't IMO. I'd just start over with the whole guiding proposition and start very simple. What makes a SSAG/mini-guider reasonable is you don't need scope rings and upper DTP's and all that, and in my time using one differential flexure non-existent. Many, many of us are getting by just fine with one.

Save complexity for later, start simple. There was a point where I thought i needed something more sensitive long ago but i decided to try the mini-guider approach with the SSAG and have not had the thought since. I live in a place where imaging opportunities can be very long interval and believe me I value my clear sky time as much as anyone.

#43 Raginar

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Posted 04 November 2013 - 11:09 AM

I guess my put on need is does he intend to keep imaging? If so, buying a 500 camera now is better than saving a few hundred but buying two cameras in 2 years or something.


I agree with the QHY5 put. Someone did a review on it and apparently it's very favorable to a lodestar.

#44 Jeff2011

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Posted 04 November 2013 - 02:21 PM

My understanding is that the lodestar has bigger pixels and a bigger chip. Also QHY has several models named similarly. The basic QHY5 chip is identical to the SSAG. The QHY5L-II mono is the more sensitive one that has been compared to the lodestar. BTW, Orion has a relationship with QHY and QHY probably makes the SSAG.

#45 zerro1

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Posted 04 November 2013 - 03:15 PM

Any less expensive options for a sensitive cam?


Unless you have a thing for buying brand new only, you need to start looking at the "used" options if you want to cut down on some of the costs. a meade DSI v1 was posted in the classifieds yesterday for $75 and sold that fast. It is the most sensitive you will find at that price and is always less expensive than the SSAG. Used SSAG's normally are listed in the $200 range and quite frankly (since I own and have used an SSAG) I'm not that impressed with them. Try plugging that SSAG into an OAG on an SCT and see how many stars you can find to guide from! I've tried, it doesn't work! Plug the Meade DSI into the same setup and you can find guide stars...

SSAG = QHY5 (QHY5 is printed on the circuit board of the SSAG)

The QHY5 II- never had any experience with them so no opinion.

Loadstar - I seen a lot of complaints over cable and connector failures that would *BLEEP* me the *bleep* off if I paid that price and had it break 3rd time out.

#46 Raginar

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Posted 04 November 2013 - 07:16 PM

I've never broke the cable other than when I was stupid. I would order a spare though. :)

#47 zerro1

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Posted 04 November 2013 - 09:30 PM

I've never broke the cable other than when I was stupid. I would order a spare though. :)


:lol:

#48 Wmacky

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Posted 05 November 2013 - 08:45 AM

Well, I decided to cover most bases. As mentioned earlier, I've ordered an adapter to alter a spare 50mm finder into a mini guider.

I've also spent a day researching the QHY5l-II / ASI120mm cameras, and it turns out there were a lot of comparisons made with the Lodestar. Almost all the posts indicated that these Aptiva chipped cams are very close to Lodestar sensitivity, with some who owned both favoring to Aptiva chip. So - I went ahead and got the ASI120MM as I had already decided to get this cam anyway for mono planetary work. Just not so soon.

I also downloaded Metaguide, and will give it a try.

Sure hope the mount works out. I really think the only worth while upgrade would be a Mach One, But that could be years down the raod for me if ever.

BTW, anyone know where I can find the default "brain" setting are in PHD?

#49 Raginar

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Posted 05 November 2013 - 10:18 PM

You using a finder guider? Try 80 15 .15 and RA and dec max motion around 1000. Calibration steps of 4000 work for me.

#50 Wmacky

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Posted 09 November 2013 - 08:36 PM

Update:

Sitting out here imaging as I type!

The finder adapter came in as well as my new ASI120MM. Got the old Celestron Finder converted to guider duty in all of 15 seconds, and screwed on the New ASI. Set the brain setting to as suggested, and well it works!

The good news; I see lots of stars. Real ones this time! Wow this cam is sensitive. I must have over 50 guide stars in every field so far.Also I have no problem seeing the DSO's to. I'm glad I got this instead of the Lodestar. I couldn't imagine needing anything more sensitive, and now I have a top tier planetary cam. I still don't know if the cure was the new, cam, or the new guide scope, or perhaps some of both. I need to to try the color cam on the new mini guider just to see.

As for the mount, I'm not sure how great it's doing. Most seem to get a smooth graph with the mini guiders, but mine is very jagged, and corrections are made on almost every frame. This said, RMS is around .27. This mount is a Mid range classic CGE. As long as It will work will enough for Short FL imaging, I guess I can get by for now until I have the funds for a Mach One.

Thanks again.






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