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Equipment Discussions >> Mounts

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mpgxsvcd
Carpal Tunnel


Reged: 12/21/11

Loc: Raleigh, North Carolina
Re: Can't get properly aligned with VX mount new [Re: will1384]
      #5824574 - 04/26/13 02:43 PM

Quote:

I have still got the Polar scope to try, and AlignMaster, then I guess I will try auto guiding, I will try the Panasonic G3 live video out as a auto guiding camera, and I also have a 50mm guide scope, a Firefly MV Mono camera, and Celestron NexImage 5, to try as a guide camera, if all that fails I will try drift alignment.

When I get good weather I will try again.




After doing some testing last night I don't think the G3 will output the live view over HDMI. It appears that the GF and G series of cameras will only output the play back mode over HDMI or RCA. The GH series will output the live view only over HDMI but some things like the crop mode and ETC will not work with live view output.

The GH3 will output everything over HDMI.

I also came to the conclusion that the Orion Mini guider package is the best option. I just bought that and will let you know how it works out.


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zawijava
scholastic sledgehammer
*****

Reged: 10/06/07

Loc: Wells, Maine 04090
Re: Can't get properly aligned with VX mount new [Re: will1384]
      #5824832 - 04/26/13 04:40 PM

I thought I remember you saying you could not see Polaris due to the trees, correct? If so, a polar scope will not be of any use.

Quote:

I have still got the Polar scope to try, and AlignMaster, then I guess I will try auto guiding, I will try the Panasonic G3 live video out as a auto guiding camera, and I also have a 50mm guide scope, a Firefly MV Mono camera, and Celestron NexImage 5, to try as a guide camera, if all that fails I will try drift alignment.

When I get good weather I will try again.




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bretm
member


Reged: 12/27/09

Re: Can't get properly aligned with VX mount new [Re: mpgxsvcd]
      #5824962 - 04/26/13 05:39 PM






If Periodic error kills the image at 1 minute doesn't it also kill the drift alignment at 1 minute? Something doesn't add up there.




Periodic error is an RA axis phenomena, while drift alignment watches motion in the DEC axis.

Bret


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will1384
member


Reged: 02/22/13

Re: Can't get properly aligned with VX mount new [Re: mpgxsvcd]
      #5825172 - 04/26/13 07:24 PM

Quote:

Quote:

I have still got the Polar scope to try, and AlignMaster, then I guess I will try auto guiding, I will try the Panasonic G3 live video out as a auto guiding camera, and I also have a 50mm guide scope, a Firefly MV Mono camera, and Celestron NexImage 5, to try as a guide camera, if all that fails I will try drift alignment.

When I get good weather I will try again.




After doing some testing last night I don't think the G3 will output the live view over HDMI. It appears that the GF and G series of cameras will only output the play back mode over HDMI or RCA. The GH series will output the live view only over HDMI but some things like the crop mode and ETC will not work with live view output.

The GH3 will output everything over HDMI.

I also came to the conclusion that the Orion Mini guider package is the best option. I just bought that and will let you know how it works out.




Its a little bit of a hidden feature, but yes the Panasonic G3 will output live video, manual focus zoom and everything, but only on the RCA plugs, you just have to hold down Q-Menu/Trash button on the camera to enable or disable it, however the manual focus zoom only zooms in about 3 times, its not enough to tell if the star is exactly centered on the camera’s screen, that’s why I was using the netbook with SharpCap, and the on screen recital, plus its a little easier to see the larger netbook screen.


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will1384
member


Reged: 02/22/13

Re: Can't get properly aligned with VX mount new [Re: zawijava]
      #5825196 - 04/26/13 07:34 PM

Quote:

I thought I remember you saying you could not see Polaris due to the trees, correct? If so, a polar scope will not be of any use.




Sometime last week I had found a small spot between two trees, that I can see Polaris, but that area has a worse view of the sky, but if I setup my telescope there, and the alignment works when using the Polar scope, I know what my problem is, it will help me narrow down the problem.


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cn register 5
scholastic sledgehammer


Reged: 12/26/12

Re: Can't get properly aligned with VX mount new [Re: will1384]
      #5826537 - 04/27/13 03:22 PM

Can someone please give a logical, rational explanation of how getting a good polar alignment will eliminate periodic error?

Chris


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Footbag
Postmaster
*****

Reged: 04/13/09

Loc: Scranton, PA
Re: Can't get properly aligned with VX mount new [Re: cn register 5]
      #5826611 - 04/27/13 04:00 PM

Quote:

Can someone please give a logical, rational explanation of how getting a good polar alignment will eliminate periodic error?

Chris




Periodic error is a measure of the bumpiness of the worm gear on the RA axis.

I see this as being unrelated to polar alignment which is a measure of how close to the polar axis the RA is aligned.

If you have a mount with a pointing model, like the Celestron, the mount will make up for polar alignment error by tracking in DEC. Typically, DEC tracking won't be as precise as RA, so that will add error, but I'm not sure if that technically would be periodic error.

If you use guiding, polar alignment error will show up as field rotation around the guide star. Unguided, it will show up as drift in dec.


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EFT
Vendor - Deep Space Products
*****

Reged: 05/07/07

Loc: Phoenix, AZ
Re: Can't get properly aligned with VX mount new [Re: cn register 5]
      #5826646 - 04/27/13 04:18 PM

Quote:

Can someone please give a logical, rational explanation of how getting a good polar alignment will eliminate periodic error?

Chris




Very simply, it won't. Two completely different problems. One is mechanical, the other is alignment.


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Madratter
Postmaster


Reged: 01/14/13

Re: Can't get properly aligned with VX mount new [Re: cn register 5]
      #5826650 - 04/27/13 04:20 PM

Quote:

Can someone please give a logical, rational explanation of how getting a good polar alignment will eliminate periodic error?

Chris




It won't. Who has suggested it would?

On the other hand, a proper polar alignment will certainly help getting good short subs, and will also help if he starts guiding. The best guiding is guiding as little as possible. This is especially true if the mount is being guided one axis at a time, which is often the case.

Edited by Madratter (04/27/13 09:19 PM)


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Stew57
Carpal Tunnel
*****

Reged: 05/03/09

Loc: Silsbee Texas
Re: Can't get properly aligned with VX mount new [Re: Madratter]
      #5826849 - 04/27/13 06:06 PM

You can use a log from phd in pecprep to see how much pe you have. PecPrep can correct for drift due to polar misalignment. I had a cgem with such bad pe a 20sec shot was star trailed at 800mm. I had one cgem that could do 2 min at the same fl with minimal star trails.

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cn register 5
scholastic sledgehammer


Reged: 12/26/12

Re: Can't get properly aligned with VX mount new [Re: Stew57]
      #5827791 - 04/28/13 06:32 AM

This guy described a tracking problem that's clearly predominantly periodic error - movement backwards and forwards rather than continual movement - yet everybody ignores this and goes on about polar alignment.

I'd start by recording the periodic error and applying it to the mount. It may be possible to use the imaging scope and camera to do this.

Chris


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DaveJ
Carpal Tunnel
*****

Reged: 01/07/05

Loc: NE Ohio
Re: Can't get properly aligned with VX mount new [Re: Footbag]
      #5827881 - 04/28/13 08:35 AM

Quote:

If you have a mount with a pointing model, like the Celestron, the mount will make up for polar alignment error by tracking in DEC. Typically, DEC tracking won't be as precise as RA, so that will add error, but I'm not sure if that technically would be periodic error.




Celestron GEMs most definitely do NOT track in DEC to make up for poor polar alignment. If DEC motions are necessary, only guiding will perform that function.


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jrcrillyAdministrator
Refractor wienie no more
*****

Reged: 04/30/03

Loc: NE Ohio
Re: Can't get properly aligned with VX mount new [Re: DaveJ]
      #5827938 - 04/28/13 09:16 AM

Quote:

Quote:

If you have a mount with a pointing model, like the Celestron, the mount will make up for polar alignment error by tracking in DEC. Typically, DEC tracking won't be as precise as RA, so that will add error, but I'm not sure if that technically would be periodic error.




Celestron GEMs most definitely do NOT track in DEC to make up for poor polar alignment. If DEC motions are necessary, only guiding will perform that function.




There are mounts that will apply model-derived dec corrections when tracking, but the list is very short. Bisque mounts can, and I think some of the new direct drive mounts can. AP may have recently added this capability. Vixen offered it in their Sky Sensor 2000 system. No Meade, no Celestron, no Losmandy...


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Footbag
Postmaster
*****

Reged: 04/13/09

Loc: Scranton, PA
Re: Can't get properly aligned with VX mount new [Re: DaveJ]
      #5828160 - 04/28/13 11:40 AM

Quote:

Quote:

If you have a mount with a pointing model, like the Celestron, the mount will make up for polar alignment error by tracking in DEC. Typically, DEC tracking won't be as precise as RA, so that will add error, but I'm not sure if that technically would be periodic error.




Celestron GEMs most definitely do NOT track in DEC to make up for poor polar alignment. If DEC motions are necessary, only guiding will perform that function.




I stand corrected. I guess they only use that for pointing.


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Cliff Hipsher
Pooh-Bah
***

Reged: 12/31/08

Loc: North Chesterfield, VA
Re: Can't get properly aligned with VX mount new [Re: Footbag]
      #5828182 - 04/28/13 11:54 AM

Quote:

Can someone please give a logical, rational explanation of how getting a good polar alignment will eliminate periodic error?

Chris




Periodic Error is caused by imperfections in the drive gear trains, specifically between the worm gear and the worm ring.

The accuracy of your polar alignment HAS NOTHING TO DO WITH, AND DOES NOT AFFECT PERIODIC ERROR. Also, each mount has its own specific amount/amplitude and frequency of Periodic Error.

To put it in different terms, Periodic Error is like having tires that are flat spotted. Polar Alignment is like have the front end aligned. You can still drive straight, but the ride is bumpy.

In this scenario, PEC (Periodic Error Correction) would be like having an intelligent active suspension system in your car. It figures out where the flat spots are and adjusts the vehicle suspension to give you a smooth ride.


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mpgxsvcd
Carpal Tunnel


Reged: 12/21/11

Loc: Raleigh, North Carolina
Re: Can't get properly aligned with VX mount new [Re: will1384]
      #5829897 - 04/29/13 10:51 AM

Quote:

Quote:

Quote:

I have still got the Polar scope to try, and AlignMaster, then I guess I will try auto guiding, I will try the Panasonic G3 live video out as a auto guiding camera, and I also have a 50mm guide scope, a Firefly MV Mono camera, and Celestron NexImage 5, to try as a guide camera, if all that fails I will try drift alignment.

When I get good weather I will try again.




After doing some testing last night I don't think the G3 will output the live view over HDMI. It appears that the GF and G series of cameras will only output the play back mode over HDMI or RCA. The GH series will output the live view only over HDMI but some things like the crop mode and ETC will not work with live view output.

The GH3 will output everything over HDMI.

I also came to the conclusion that the Orion Mini guider package is the best option. I just bought that and will let you know how it works out.




Its a little bit of a hidden feature, but yes the Panasonic G3 will output live video, manual focus zoom and everything, but only on the RCA plugs, you just have to hold down Q-Menu/Trash button on the camera to enable or disable it, however the manual focus zoom only zooms in about 3 times, its not enough to tell if the star is exactly centered on the camera’s screen, that’s why I was using the netbook with SharpCap, and the on screen recital, plus its a little easier to see the larger netbook screen.




Cool. Thanks for that tip. You learn something new everyday.


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Kraus
Pooh-Bah


Reged: 03/10/12

Loc: Georgia.
Re: Can't get properly aligned with VX mount new [Re: mpgxsvcd]
      #5830081 - 04/29/13 12:36 PM


In conclusion, all of the above responses is why I gave up astrophotography. What a headache.


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mpgxsvcd
Carpal Tunnel


Reged: 12/21/11

Loc: Raleigh, North Carolina
Re: Can't get properly aligned with VX mount new [Re: Kraus]
      #5830391 - 04/29/13 02:39 PM

Quote:


In conclusion, all of the above responses is why I gave up astrophotography. What a headache.




All it would take is one simple video demonstration that shows you exactly what to do and what not to do. I am surprised no one has done that yet?


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Footbag
Postmaster
*****

Reged: 04/13/09

Loc: Scranton, PA
Re: Can't get properly aligned with VX mount new [Re: Kraus]
      #5834658 - 05/01/13 03:28 PM

Quote:


In conclusion, all of the above responses is why I gave up astrophotography. What a headache.




You have to enjoy the headache, otherwise you won't succeed.


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WesC
Carpal Tunnel
*****

Reged: 02/06/13

Loc: La Crescenta, CA
Re: Can't get properly aligned with VX mount new [Re: Kraus]
      #5834831 - 05/01/13 05:15 PM

Quote:


In conclusion, all of the above responses is why I gave up astrophotography. What a headache.




Yeah and why I am reluctant to jump in. From what I can see, its has a lot to do with how much money you spend. The better quality the mount and software, the less trouble you'll have. The people who enjoy it the most and take the best images are the ones with the most money and time to throw at it.


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