First Guiding Attempt in a While
- fatboy1271
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First Guiding Attempt in a While
As was the case the other night my PHD2 live feed was washed out regardless of what exposure setting I used. Instead of beating my head against the wall I did a Reset in PHD2 and so glad I did!!! I do my Polar Alignments with the PoleMaster. My Alignment routine is done through the new CPWI, which I love once I got used to it; although there's not really much of a learning curve.
Once Guiding under RMS Error [px] my Tot would occasionally fluctuate between 0.18 and 0.33; however, it mainly stayed right around 0.18. I'm not very familiar with Guiding but that seems pretty good to me
I was taking 300sec at 800ISO and getting round stars as far as I could tell! I still need to do some tests to see if in my Light Pollution 300 at 800ISO is better than at 1600ISO, which gets pretty washed out. Also, I wonder if say 150sec at 1600ISO would be better than 300 at 800ISO...
Attached are two files:
Guiding graph Roundness of star at 300sec (Subject is M14) Thanks to anyone reading this and any comments/suggestions are always welcome!
fat
Mount: Celestron Advanced VX
Gear: Canon 70D / Hutech LPS-D1-48 / ES 2" Field Flattener / QHY PoleMaster / Celestron GPS / ZWO ASI120MC / Orion 50mm Guide Scope / ZWO EAF
Software: CPWI / PHD2 / N.I.N.A / Stellarium/StellariumScope/Remote Control / PI / RegiStax 6 / AutoStakkert!2 / PIPP | Retired? BackyardEOS Premium
EPs: Stock Celestron 9mm and 24mm / Celestron Omni 32mm (I love this one!) / Celestron X-Cel LX 3x Barlow (I think 2X would have been smarter...)
Support Staff (Loved Ones!): CeCe, Ro, and Geno
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- Juno16
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Re: First Guiding Attempt in a While
I’ve never seen PHD rms numbers like yours with my AVX. I’d be thrilled with double that!
Good for you!
Thanks,
Jim
Scopes: Explore Scientific ED102 APO, Sharpstar 61 EDPH II APO, Samyang 135 F2 (still on the Nikon).
Mount: Skywatcher HEQ5 Pro with Rowan Belt Mod
Stuff: ASI EAF Focus Motor (x2), ZWO OAG, ZWO 30 mm Guide Scope, ASI 220mm min, ASI 120mm mini, Stellarview 0.8 FR/FF, Sharpstar 0.8 FR/FF, Mele Overloock 3C.
Camera/Filters/Software: ASI 533 mc pro, ASI 120mm mini, ASI 220mm mini , IDAS LPS D-1, Optolong L-Enhance, ZWO UV/IR Cut, N.I.N.A., Green Swamp Server, PHD2, Adobe Photoshop CC, Pixinsight.
Dog and best bud: Jack
Sky: Bortle 6-7
My Astrobin: https://www.astrobin.com/users/Juno16/
- JayTee
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Re: First Guiding Attempt in a While
When you "auto guide" the very first thing you do after the image is complete and displays on your screen is to check the shape of your stars. They are either round or they're not. If they are, then YAY, if not then you need to develop a troubleshooting routine. Each imaging system is slightly different so your procedure/routine may or may not mimic mine.
So, what shape were your stars?
Also, in PHD2 don't gauge your guiding by using how many pixels your error is. Instead, use arcseconds, that is a much more meaningful measure of your guiding accuracy. This number is meaningful once you calculate what your imaging scale (not guiding) scale is. This all depends on the image scale of your main system and what you are trying to accomplish. If the RMS guiding error is 0.8 arc-sec, how does that translate to the number of pixels of movement on your main images? If you are working with a long focal length set-up and a main-camera image scale of well under 1 arc-sec/px, you might decide you need better guiding. With a shorter focal length setup for your main camera, this accuracy is probably fine. Measure the star-sizes in your main images and look at the star-sizes and elongation. Those are the only reliable ways to judge if the guiding is truly good enough. We sometimes point to a total guiding RMS of 1 arc-sec as a reasonable target for most set-ups, but that’s only a very rough starting point.
Cheers,
JT
∞ AP Scopes: #1: TPO 6" f/9 RC #2: ES 102 f/7 APO #3: ES 80mm f/6 APO
∞ G&G Scopes: #1: Meade 102mm f/7.8 #2: Bresser 102mm f/4.5
∞ Guide Scopes: 70 & 80mm fracs -- The El Cheapo Bros.
∞ Mounts: iOptron CEM70AG, SW EQ6R, Celestron AVX, SLT & GT (Alt-Az), Meade DS2000
∞ Cameras: #1: ZWO ASI294MC Pro #2: 662MC #3: 120MC, Canon T3i, Orion SSAG, WYZE Cam3
∞ Binos: 10X50,11X70,15X70, 25X100 ∞ AP Gear: ZWO EAF and mini EFW and the Optolong L-eXteme filter
∞ EPs: ES 2": 21mm 100° & 30mm 82° Pentax XW: 7, 10, 14, & 20mm 70°
Searching the skies since 1966. "I never met a scope I didn't want to keep."
- fatboy1271
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Re: First Guiding Attempt in a While
Thanks Jim! I hope to get out again soon to continue working on Guiding. I see JT has some more learnin' for me to do...
fat
Mount: Celestron Advanced VX
Gear: Canon 70D / Hutech LPS-D1-48 / ES 2" Field Flattener / QHY PoleMaster / Celestron GPS / ZWO ASI120MC / Orion 50mm Guide Scope / ZWO EAF
Software: CPWI / PHD2 / N.I.N.A / Stellarium/StellariumScope/Remote Control / PI / RegiStax 6 / AutoStakkert!2 / PIPP | Retired? BackyardEOS Premium
EPs: Stock Celestron 9mm and 24mm / Celestron Omni 32mm (I love this one!) / Celestron X-Cel LX 3x Barlow (I think 2X would have been smarter...)
Support Staff (Loved Ones!): CeCe, Ro, and Geno
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- fatboy1271
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Re: First Guiding Attempt in a While
Hey JT,JayTee wrote: ↑Wed Aug 07, 2019 12:42 am Congrats,
When you "auto guide" the very first thing you do after the image is complete and displays on your screen is to check the shape of your stars. They are either round or they're not. If they are, then YAY, if not then you need to develop a troubleshooting routine. Each imaging system is slightly different so your procedure/routine may or may not mimic mine.
So, what shape were your stars?
Also, in PHD2 don't gauge your guiding by using how many pixels your error is. Instead, use arcseconds, that is a much more meaningful measure of your guiding accuracy. This number is meaningful once you calculate what your imaging scale (not guiding) scale is. This all depends on the image scale of your main system and what you are trying to accomplish. If the RMS guiding error is 0.8 arc-sec, how does that translate to the number of pixels of movement on your main images? If you are working with a long focal length set-up and a main-camera image scale of well under 1 arc-sec/px, you might decide you need better guiding. With a shorter focal length setup for your main camera, this accuracy is probably fine. Measure the star-sizes in your main images and look at the star-sizes and elongation. Those are the only reliable ways to judge if the guiding is truly good enough. We sometimes point to a total guiding RMS of 1 arc-sec as a reasonable target for most set-ups, but that’s only a very rough starting point.
Cheers,
JT
Thanks for the info; I appreciate your time writing all that up. I understand what you mean by guiding numbers don't mean squat if you don't have round stars.
Last night I was tracking for 600sec! I'm hoping to try again tonight and see if I can get another batch of M31. Separate question is whether or not shooting at 600sec x 400ISO is better than 300sec x 800ISO.
Anyway, as to PHD2 numbers, is this the arcsecond setting you are talking about? Here is a screenshot of a couple stars near M51. It's zoomed in at 328% in BYEOS: They look round to me... What do you think? Am I on the right track?
Thanks again,
fat
Mount: Celestron Advanced VX
Gear: Canon 70D / Hutech LPS-D1-48 / ES 2" Field Flattener / QHY PoleMaster / Celestron GPS / ZWO ASI120MC / Orion 50mm Guide Scope / ZWO EAF
Software: CPWI / PHD2 / N.I.N.A / Stellarium/StellariumScope/Remote Control / PI / RegiStax 6 / AutoStakkert!2 / PIPP | Retired? BackyardEOS Premium
EPs: Stock Celestron 9mm and 24mm / Celestron Omni 32mm (I love this one!) / Celestron X-Cel LX 3x Barlow (I think 2X would have been smarter...)
Support Staff (Loved Ones!): CeCe, Ro, and Geno
Let's Go Pens!!!
- Jennifer Christine
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Re: First Guiding Attempt in a While
I notice in your original image that thetre is a lot of noise and stars are suffering from compression artifacts. Make sure you process in tiff format at 16 bit.
Canon lenses 100 to 400 L series, 18 to 135 usm.
Mount's, 2x alt az, 2 x eq (adventurer an neq6pro.)
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- JayTee
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Re: First Guiding Attempt in a While
Plus, when you screw up a 10 minute exposure you've lost 10 minutes of imaging time, but if you screw up a three-minute exposure you've only lost three minutes and there's still seven more minutes to go in that 10 minute period where you could get in 2 more images.
Cheers,
JT
∞ AP Scopes: #1: TPO 6" f/9 RC #2: ES 102 f/7 APO #3: ES 80mm f/6 APO
∞ G&G Scopes: #1: Meade 102mm f/7.8 #2: Bresser 102mm f/4.5
∞ Guide Scopes: 70 & 80mm fracs -- The El Cheapo Bros.
∞ Mounts: iOptron CEM70AG, SW EQ6R, Celestron AVX, SLT & GT (Alt-Az), Meade DS2000
∞ Cameras: #1: ZWO ASI294MC Pro #2: 662MC #3: 120MC, Canon T3i, Orion SSAG, WYZE Cam3
∞ Binos: 10X50,11X70,15X70, 25X100 ∞ AP Gear: ZWO EAF and mini EFW and the Optolong L-eXteme filter
∞ EPs: ES 2": 21mm 100° & 30mm 82° Pentax XW: 7, 10, 14, & 20mm 70°
Searching the skies since 1966. "I never met a scope I didn't want to keep."
- fatboy1271
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Re: First Guiding Attempt in a While
Hey JT!JayTee wrote: ↑Tue Aug 20, 2019 9:28 pm Here's my philosophy on exposure time and ISO. I try to use 1600 ISO whenever possible. It means that my exposure time will be shorter. I can process out the noise from the higher ISO but I can't fix the guiding errors that inherently pop-up with longer and longer exposures. It is a trade-off though because I believe the SNR is better on longer exposures, but the issue once again is that shorter exposures are less prone to guiding errors.
Plus, when you screw up a 10 minute exposure you've lost 10 minutes of imaging time, but if you screw up a three-minute exposure you've only lost three minutes and there's still seven more minutes to go in that 10 minute period where you could get in 2 more images.
Cheers,
JT
Earlier today I posted My Exposure+ISO Test and pretty much found the same answer that you just gave! The 600sec x 400ISO has less noise but I think the 180sec x 800ISO has slightly more detail. Therefore, the extra time spent imaging one shot is not worth it. Especially with
The biggest issue is that if I shoot at 1600ISO I will be stuck most likely around 60 seconds. I haven't confirmed that but my
Thanks for your time!
fat
Mount: Celestron Advanced VX
Gear: Canon 70D / Hutech LPS-D1-48 / ES 2" Field Flattener / QHY PoleMaster / Celestron GPS / ZWO ASI120MC / Orion 50mm Guide Scope / ZWO EAF
Software: CPWI / PHD2 / N.I.N.A / Stellarium/StellariumScope/Remote Control / PI / RegiStax 6 / AutoStakkert!2 / PIPP | Retired? BackyardEOS Premium
EPs: Stock Celestron 9mm and 24mm / Celestron Omni 32mm (I love this one!) / Celestron X-Cel LX 3x Barlow (I think 2X would have been smarter...)
Support Staff (Loved Ones!): CeCe, Ro, and Geno
Let's Go Pens!!!
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Re: First Guiding Attempt in a While
Hope this helps,
JT
∞ AP Scopes: #1: TPO 6" f/9 RC #2: ES 102 f/7 APO #3: ES 80mm f/6 APO
∞ G&G Scopes: #1: Meade 102mm f/7.8 #2: Bresser 102mm f/4.5
∞ Guide Scopes: 70 & 80mm fracs -- The El Cheapo Bros.
∞ Mounts: iOptron CEM70AG, SW EQ6R, Celestron AVX, SLT & GT (Alt-Az), Meade DS2000
∞ Cameras: #1: ZWO ASI294MC Pro #2: 662MC #3: 120MC, Canon T3i, Orion SSAG, WYZE Cam3
∞ Binos: 10X50,11X70,15X70, 25X100 ∞ AP Gear: ZWO EAF and mini EFW and the Optolong L-eXteme filter
∞ EPs: ES 2": 21mm 100° & 30mm 82° Pentax XW: 7, 10, 14, & 20mm 70°
Searching the skies since 1966. "I never met a scope I didn't want to keep."
- Juno16
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Re: First Guiding Attempt in a While
I saw the histogram for a 600 second iso 400 image in your post. Somebody help me out here, but I always thought that you should shoot for 1/4 to 1/3 from the left. Yours are way up there close to 3/4. That explains why you are shooting much longer exposures than I am. I recently had some images where the histogram peak was almost halfway shooting at iso 400 for 150 seconds.
My thinking could be way off. Can anyone comment?
Thanks,
Jim
Scopes: Explore Scientific ED102 APO, Sharpstar 61 EDPH II APO, Samyang 135 F2 (still on the Nikon).
Mount: Skywatcher HEQ5 Pro with Rowan Belt Mod
Stuff: ASI EAF Focus Motor (x2), ZWO OAG, ZWO 30 mm Guide Scope, ASI 220mm min, ASI 120mm mini, Stellarview 0.8 FR/FF, Sharpstar 0.8 FR/FF, Mele Overloock 3C.
Camera/Filters/Software: ASI 533 mc pro, ASI 120mm mini, ASI 220mm mini , IDAS LPS D-1, Optolong L-Enhance, ZWO UV/IR Cut, N.I.N.A., Green Swamp Server, PHD2, Adobe Photoshop CC, Pixinsight.
Dog and best bud: Jack
Sky: Bortle 6-7
My Astrobin: https://www.astrobin.com/users/Juno16/
- JayTee
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Re: First Guiding Attempt in a While
Look at the post right above yours!
JT
∞ AP Scopes: #1: TPO 6" f/9 RC #2: ES 102 f/7 APO #3: ES 80mm f/6 APO
∞ G&G Scopes: #1: Meade 102mm f/7.8 #2: Bresser 102mm f/4.5
∞ Guide Scopes: 70 & 80mm fracs -- The El Cheapo Bros.
∞ Mounts: iOptron CEM70AG, SW EQ6R, Celestron AVX, SLT & GT (Alt-Az), Meade DS2000
∞ Cameras: #1: ZWO ASI294MC Pro #2: 662MC #3: 120MC, Canon T3i, Orion SSAG, WYZE Cam3
∞ Binos: 10X50,11X70,15X70, 25X100 ∞ AP Gear: ZWO EAF and mini EFW and the Optolong L-eXteme filter
∞ EPs: ES 2": 21mm 100° & 30mm 82° Pentax XW: 7, 10, 14, & 20mm 70°
Searching the skies since 1966. "I never met a scope I didn't want to keep."
- Juno16
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Re: First Guiding Attempt in a While
Still have sleep in my eyes! Answers my question though, thanks!
Jim
Scopes: Explore Scientific ED102 APO, Sharpstar 61 EDPH II APO, Samyang 135 F2 (still on the Nikon).
Mount: Skywatcher HEQ5 Pro with Rowan Belt Mod
Stuff: ASI EAF Focus Motor (x2), ZWO OAG, ZWO 30 mm Guide Scope, ASI 220mm min, ASI 120mm mini, Stellarview 0.8 FR/FF, Sharpstar 0.8 FR/FF, Mele Overloock 3C.
Camera/Filters/Software: ASI 533 mc pro, ASI 120mm mini, ASI 220mm mini , IDAS LPS D-1, Optolong L-Enhance, ZWO UV/IR Cut, N.I.N.A., Green Swamp Server, PHD2, Adobe Photoshop CC, Pixinsight.
Dog and best bud: Jack
Sky: Bortle 6-7
My Astrobin: https://www.astrobin.com/users/Juno16/
- fatboy1271
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Re: First Guiding Attempt in a While
At 60sec x 1600ISO I can't get to the Left 1/3. I'm at 1/2, slightly left. At 180sec x 800ISO I'm at 1/2, slightly right. 60 seconds seems awfully short when I can easily achieve 180sec+. How would you approach my situation?
60sec x 1600ISO 180sec x 800ISO
Mount: Celestron Advanced VX
Gear: Canon 70D / Hutech LPS-D1-48 / ES 2" Field Flattener / QHY PoleMaster / Celestron GPS / ZWO ASI120MC / Orion 50mm Guide Scope / ZWO EAF
Software: CPWI / PHD2 / N.I.N.A / Stellarium/StellariumScope/Remote Control / PI / RegiStax 6 / AutoStakkert!2 / PIPP | Retired? BackyardEOS Premium
EPs: Stock Celestron 9mm and 24mm / Celestron Omni 32mm (I love this one!) / Celestron X-Cel LX 3x Barlow (I think 2X would have been smarter...)
Support Staff (Loved Ones!): CeCe, Ro, and Geno
Let's Go Pens!!!
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