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Squiggly lines in long exposure


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Not sure of your focal length your at but it's very hard to get even the most expensive mount to track well over 2 minutes with good results at longer lengths. Until you try auto guiding with your mou

I've just copied this from the Celestron website on the section devoted to your mount. You’ll be able to track through long exposures using permanently programmable periodic error correction. I don't

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I've just copied this from the Celestron website on the section devoted to your mount.

You’ll be able to track through long exposures using permanently programmable periodic error correction.

I don't know what others think of this claim, which makes no mention of autoguiding, but I know what I think of it. I think it should land Celestron in court.

Olly

To say Celestron are being economical with the truth is a slight understatement.

Perhaps only slightly less despicable than this misleading bit of marketing

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Edited by johnrt
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Similarly (I will not start to spam the forum just to be allowed to edit my posts) without any specifics the statement from Celestron basically says that unguided plus PA correction should work better than unguided. My assumption also includes that the user didn't mess anything up too much when setting up PA correction or polar alignment.

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I've just copied this from the Celestron website on the section devoted to your mount.

You’ll be able to track through long exposures using permanently programmable periodic error correction.

I don't know what others think of this claim, which makes no mention of autoguiding, but I know what I think of it. I think it should land Celestron in court.

Olly

Well I've previously done 180s unguided exposures on my AVX without PEC correction. I suppose it depends on what you call 'long exposures'! Mind you, I think that was just with a 1100d @ 300mm :):tongue:

Louise

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Well I've previously done 180s unguided exposures on my AVX without PEC correction. I suppose it depends on what you call 'long exposures'! Mind you, I think that was just with a 1100d @ 300mm :):tongue:

Louise

The Celestron quote I copied/pasted was from the setup of the OP with a two metre focal length. 2M, not 300mm. That does kind of change things...

I'd venture as far as saying that depending on what you call a "long exposure", your pixel size and the focal length I can't say that the statement is untrue.

Sorry but which statement, mine or Celestron's? Long exposures at 2 metres using only PEC and no autoguiding? I don't believe that 'a man on a Clapham omnibus' - an imaginary representation of an ordinary person in English law, would be able to do long exposures that way. I think the statement is misleading to beginners. In my own business I would never make any claim which stretched the boundaries of probability to such an extent.

Olly

Edit, they don't claim that stars will be round but a reasonable person would assume that to be the case if you are 'able to track through long exposures.' The key word would be 'track.' What does the word mean?

Edited by ollypenrice
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The Celestron quote I copied/pasted was from the setup of the OP with a two metre focal length. 2M, not 300mm. That does kind of change things...

Sorry but which statement, mine or Celestron's? Long exposures at 2 metres using only PEC and no autoguiding? I don't believe that 'a man on a Clapham omnibus' - an imaginary representation of an ordinary person in English law, would be able to do long exposures that way. I think the statement is misleading to beginners. In my own business I would never make any claim which stretched the boundaries of probability to such an extent.

Olly

Edit, they don't claim that stars will be round but a reasonable person would assume that to be the case if you are 'able to track through long exposures.' The key word would be 'track.' What does the word mean?

Yeah, they use the same blurb for all AVX configurations, including the mount alone! Sales blurb is always best taken with a large pinch of salt!

Louise

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Has anyone actually got any idea what the periodic error is on these mounts? I would guess similar to the HEQ5/EQ6, i.e. maybe around 10-40  arcsec peak-to-peak. From that and your pixel scale you can work out (guestimate!) how long an exposure you can do (at a given Declination of course).

NigelM

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Sorry but which statement, mine or Celestron's? Long exposures at 2 metres using only PEC and no autoguiding? I don't believe that 'a man on a Clapham omnibus' - an imaginary representation of an ordinary person in English law, would be able to do long exposures that way. I think the statement is misleading to beginners. In my own business I would never make any claim which stretched the boundaries of probability to such an extent.

 

Olly

 

Edit, they don't claim that stars will be round but a reasonable person would assume that to be the case if you are 'able to track through long exposures.' The key word would be 'track.' What does the word mean?

Sorry I should have been clearer, I meant the Celestron statement. The text has been carefully edited so that it is mostly void of any real information like most ad copy. If that text was actionable the Clapham man would be a very busy man (disclaimer: I'm not a lawyer and if I was I would be a Swedish lawyer but I have heard about the Clapham man on QI).

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