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Piggybacking camera on ETX80 -safe ?

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#1 El Sid

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Posted 28 March 2013 - 09:34 AM

I have currently got my Sony DSC H2 ( quite a large digicam, DSLR sized almost ) mounted on my ETX80, via an adaptor I made that drops in to the top port like an eyepiece.
What I would like to do is make another adaptor which allows me to use the scope as well as the camera - i.e. mounting the camera on the tube. In the picture below I have the 45 degree spotting scope attachment fitted to the other port but it severely limits elevation.
This new mount will add a little more weight ( even though I'll try to keep most of the weight over the pivot ) and I'm worried about it damaging the gears. Should I be concerned ?
How about if I switch to polar from alt\az ? would that make matters better or worse ?

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#2 Stew57

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Posted 28 March 2013 - 09:55 AM

If you could achieve balance it would probably be OK. The ETX 809 does not make balancing easily done and the gears are nylon (easily damaged). That said have a guide scope mounted with a mallincam in the eyepiece holder and it is working fine. But then again I was not worried if I broke something.

#3 El Sid

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Posted 28 March 2013 - 11:16 AM

Thanks !

What is the correct point of balance for the ETX 60\70\80 ? I ask because I'm sure I read somewhere that it's designed to be a little nose heavy to preload the alt gears, but that could be completely wrong of course.
With the dew shield installed and any of the provided eyepieces fitted the weight is biased to the front.
Maybe I'm overcomplicating the situation - all I require from the mount is that it will track well enough for a 30 sec exposure ( that's the longest that the Sony DSC is capable of )

#4 Stew57

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Posted 28 March 2013 - 02:00 PM

With a heavy camera in the back you could have too much out of balance weight for the mount gears to handle. Yes, the ETX 80 has a spring in the DEC axis that gives the scope a nose heavy push. With your equipment installed and the DEC clutch disengaged, is the scope balanced or slightly nose heavy? Are you using the scope in polar mode or alt/az?

#5 Starman27

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Posted 28 March 2013 - 02:08 PM

Clever camera mount adapter.

#6 El Sid

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Posted 28 March 2013 - 04:42 PM

Thanks for the kind comment Starman - the adapter is just a piece of steel plate brazed to some 1-1/4" tube.

Stew57 - I haven't actually tried running the mount under power yet with the camera fitted. I have never actually had much success aligning it. With the Dec clutch disengaged it's slightly rear heavy. The new mount will place the camera forwards of course. I'd like to run it in polar mode eventually, I'm assuming that will increase the accuracy ?
I know the ETX-80 is not intended for astrophotography but I'm hoping it'll handle the short exposures my camera is capable of.
Thanks for your help so far, I am really new to this - I have spent most of my life in a heavily light polluted area of the UK where the sky is usually a dull orange colour ( when it isn't snowing or raining ) and the only real targets are the moon and the brighter planets. Now I live in a rural area of Spain with clear dark skies and I'm like a kid in a 'candy store' ;)

#7 Stew57

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Posted 28 March 2013 - 07:31 PM

I would be willing to buy you a CGE Pro if you could send me your dark skies! If the weight is just slightly rear heavy I would think it would be no problem. Here are some pictures of my ETX80 setup. I would think your loading is about the same or less.


http://s906.photobuc...&postlogin=true


The key to getting a good alignment is calibrating motors and training the drives. Don't rely on a 1 star alignment either. If objects don't land close enough use the high precision mode.

#8 El Sid

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Posted 29 March 2013 - 07:24 AM

Thanks for the pictures of your setup - that is pretty amazing - if I could send you some clear dark skies I would ;)
I got some imaging done last night, there is currently a short time window between full darkness and moonrise I was able to take advantage of. I really need to get the mount aligned and tracking because the camera is capable of taking some very nice images considering it's a very cheap non-DSLR.
I'll figure it out...
We are moving soon to a new place where I can set up a permanent observatory, that will help.

One question - daylight saving time in the Autostar menu - does that mean " my country uses the daylight saving system " or " my country uses the the daylight saving system and it is currently in effect " ? the manual isn't much help on that point.

Thanks again !

#9 Stew57

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Posted 29 March 2013 - 11:12 AM

If you are going to take short exposures, stack and process you should do better than me. Here are some pics in a 2min youtube video. http://www.youtube.c...h?v=C_iv2EF7DkA

I think it is the "my country uses the the daylight saving system and it is currently in effect" as I have had to turn it off before. I don't believe it is important except for getting the alignment stars close at the start. Once aligned the sky model is shifted and would compensate for being off a bit on the time.

#10 El Sid

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Posted 29 March 2013 - 04:12 PM

Thanks Mark - you have some great images there.






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