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Imaging with AVX and ZWO


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So, I'm still very new with my Celestron AVX mount. I took it out, used my phone to tell me north and aligned the tripod peg that way, the ground was pretty level. This was my back garden so I took solar system align and just used Jupiter. Seemed to work fine, I then Slew to Mars (my imaging target), it didn't centre it great.

Anyways used the hand controller and centred and started to image with Sharpecap and my ZWO asi 120. My question is this, during the capture the Mars was driting a bit and I would make small adjustments using the hand controller, say every 30sec. I assumed that when I used autostackert later I would just ditch the bad frames from the movement - does this manual hand controller tracking really hurt the image quality ?

I've yet to use my AVX on a great night, so Im literally clueless as to how good it tracking can be, should I expect to actually keep a planet in the center of the frame for 5min without any manual interaction? Btw my AVX aligment is all the two star system I don't have a polar scope.

Attacehd is what I got, taken from city center backyard, 2x barlow, 8 inch, and loads of wobble/heat haze when looking in the eye peice and massive wavelet processing :)

mars_18_11_22.png

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I use an AVX as well. If you want the best performance then you have to polar align but you don't need to do that for planetary imaging (I don't). Just do an accurate 2 star align. It's not unusual to have to slightly adjust it when doing planetary imaging - just keep it more or less central.

If you do an accurate 2 star align and PA the AVX will be good for 2 min exposures without guiding. I generally guide for DSOs and do 5 min exposures with no issues.

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16 hours ago, RosalinaandLuma said:

So, I'm still very new with my Celestron AVX mount. I took it out, used my phone to tell me north and aligned the tripod peg that way, the ground was pretty level. This was my back garden so I took solar system align and just used Jupiter. Seemed to work fine, I then Slew to Mars (my imaging target), it didn't centre it great.

Anyways used the hand controller and centred and started to image with Sharpecap and my ZWO asi 120. My question is this, during the capture the Mars was driting a bit and I would make small adjustments using the hand controller, say every 30sec. I assumed that when I used autostackert later I would just ditch the bad frames from the movement - does this manual hand controller tracking really hurt the image quality ?

I've yet to use my AVX on a great night, so Im literally clueless as to how good it tracking can be, should I expect to actually keep a planet in the center of the frame for 5min without any manual interaction? Btw my AVX aligment is all the two star system I don't have a polar scope.

 

If you don't have one, it is worth getting an illuminated reticle eyepiece - it doesn't have to be expensive - I have one of these:  Svbony 12mm reticle eyepiece

This will help ensure the alignment stars are centred in the eyepiece when setting up. It's amazing how far out you can be from centre - especially if using a wider eyepiece.

If you pay the £12 licence fee for Sharpcap that enables the polar aligment feature that you can do with your camera  -although I am not sure whether an ASI120 on a 8" SCT will give a big enough field of view for this to work. Be aware that the polarscope for the AVX (if you choose to buy one) has limited use because the altitude adjustment knobs prevent you from easily looking through it. I had one, tried to use it twice and sold it on.

21 minutes ago, bosun21 said:

You also have to ensure that your tripod and mount are level otherwise it will drift for sure.

There is plenty of advice on this forum and elsewhere that you only need to be roughly level. 

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14 hours ago, bosun21 said:

I don’t agree with you on this. Especially at high magnification.

Which bit don't you agree with?

It is correct that you only need to be approximately level. If you are correctly polar aligned, it should not matter. The only issue with not being level is a single star alignment will lead to inaccurate go-to's. 3 star alignment should remove the problem and give accurate goto's. Tracking should not be affected as you will be on the same rotational axis.

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If you have an EQ5 mount which tracks only in RA then say for instance you are tracking a planet on the ecliptic . If you are not level then the RA can’t compensate for a path of travel that is moving askew to the ecliptic. Basic geometry.

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1 hour ago, bosun21 said:

But you are not on the same rotational axis if you are not level 

Yes you will be. The centre of the RA axis will be pointed at the pole regardless of the mount tilt. If the mount being perfectly level was critical, we would be taking levels to our mounts to get them perfect. The measured RA / DEC might be wrong (hence the goto issue), but the axis will be correct.

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2 hours ago, bosun21 said:

you are not on the same rotational axis

Imagine the mount head -only the mount- suspended in space with the RA axis pointing at the pole. It matters not how you keep it there. It doesn't need to be a tripod or support from underneath even. 

Whilst leveling the tripod does no harm, it's also unnecessary. 

The only time I can think when levelling may be useful is to have some sort of set-up reference if you tear down end of session. But then again, you're going to align anyway so ..

Cheers.

Edited by alacant
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54 minutes ago, alacant said:

Imagine the mount head -only the mount- suspended in space with the RA axis pointing at the pole. It matters not how you keep it there. It doesn't need to be a tripod or support from underneath even. 

Whilst leveling the tripod does no harm, it's also unnecessary. 

The only time I can think when levelling may be useful is to have some sort of set-up reference if you tear down end of session. But then again, you're going to align anyway so ..

Cheers.

 

1 minute ago, bosun21 said:

So I’ve been wasting my time painstakingly reaching a perfect level? I live and learn. What about an alt/az go to?

Yes. The fixed part of the mount is tilted N-S anyway, to your local latitude's angle with Polaris. The E-W axis just affects the time, which is re-calibrated by the star alignment. The very EQ6-like Takahashi EM200 mounts cannot be leveled since the legs are of a fixed length. If doing a drift alignment a level mount reduces the interaction between axes during the alignment process but not by much. Time would be better spent refining polar alignment than in aligning your pier with the centre of the Earth:! That's all you're doing, in the end...

Olly

 

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4 hours ago, bosun21 said:

If you have an EQ5 mount which tracks only in RA then say for instance you are tracking a planet on the ecliptic . If you are not level then the RA can’t compensate for a path of travel that is moving askew to the ecliptic. Basic geometry.

But it's not it's a Avx, as stated it's a Gem( German equatorial mount which to get the best performance from should be polar aligned therefore tracking the equatorial plane .. 

So no confusion for me😜

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1 hour ago, newbie alert said:

But it's not it's a Avx, as stated it's a Gem( German equatorial mount which to get the best performance from should be polar aligned therefore tracking the equatorial plane .. 

So no confusion for me😜

I’m asking about the Alt/Az go to for myself as I also have a 127 go to as well as my EQ 

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