My journey has began

kaomoo · Post by **kaomoo** » Thu Aug 18, 2011 1:56 pm

Tiring session last night. Started WAY too late. Didn't have familiar southern bright stars to align with. Very disappointing alignment result. Made worse by bad polar alignment.
Only fruitful bit was visual observation of Jupiter and its 4 bright moons. Managed to crank up to 9mm EP with 2x barrow on primary of 2032mm. But due to bad tracking, keep leaving FOV. Also.. sigh, as Gary found out, my condo floor vibrates a fair bit.... After a while, my eyes were twitching too!..

patience.....

orly_andico · Post by **orly_andico** » Thu Aug 18, 2011 2:30 pm

celestron vibration pads?

cloud_cover · Post by **cloud_cover** » Thu Aug 18, 2011 2:54 pm

[quote="kaomoo"... Plus due to cloud cover, everything is near zenith and it was killing my back and neck..... anyone keen to give it a whirl?[/quote]

Hey, its not my fault! I'm not even in Singapore!

Heh..... jokes aside, if you're solely doing visual, try to align using a compass first and set your altitude to just above 0 deg. This is usually enough for visual alignment.
Also, it helps greatly to align your finderscope to the main telescope using a terrestrial object (such as a neighbour's light - lights are easy and usually bright enough you can tell its just out of the FOV due to the scattered glare)
After you have run an all-star polar align routine on your CGEM, you generally no longer need to adjust the latitude unless you're imaging with the C8, in which a drift alignment is almost mandatory. This of course, assumes your mount is perfectly level - get a good spirit level, not the $2 China ones. Basically if the spirit level shows tilt when placed on the shop's floor, or different levels show different readings, you know you have a problem

I suspect if you're imaging through your ST80, drift alignment may not be that necessary.(suspicion only)

orly_andico · Post by **orly_andico** » Thu Aug 18, 2011 3:40 pm

incorrect suspicion, kevin.

i was snapping shots last night with my Z70 @ 336mm (with reducer) and getting oblong stars at 100% with 30-second exposures. so yes, drift alignment needed..

kaomoo · Post by **kaomoo** » Thu Aug 18, 2011 5:34 pm

orly_andico wrote:celestron vibration pads?

yes, but not when it's 150SGD for a set of 3. I will need to source.

also finding a firmer ground would be good.

orly_andico · Post by **orly_andico** » Thu Aug 18, 2011 5:40 pm

One of my observing buddies back in Manila (who incidentally was the guy who originally wrote EQMOD) found a way to DIY those vibration pads.

You need those black rubber "cups" that they sell in DIY shop that are used for chair legs and stuff.

Get the biggest ones you can find. Fill up the cup with silicone adhesive (also used for affixing secondary mirrors to their holders.. and sealing leaky windshields) and wait for it to cure.

He actually bothered to benchmark them versus the Celestron pads in terms of damping time, they were not as good, but were still a significant improvement, and are dirt-cheap.

kaomoo · Post by **kaomoo** » Thu Aug 18, 2011 5:41 pm

cloud_cover wrote:
Hey, its not my fault! I'm not even in Singapore!

ha ha ha. holiday? won't you just on nights?

Heh..... jokes aside, if you're solely doing visual, try to align using a compass first and set your altitude to just above 0 deg. This is usually enough for visual alignment.

yup. need to find a decent analog compass. Phone compass just don't cut it.

Also, it helps greatly to align your finderscope to the main telescope using a terrestrial object (such as a neighbour's light - lights are easy and usually bright enough you can tell its just out of the FOV due to the scattered glare)

finder/scope alignment i have more or less master. helps not to use diagonals

After you have run an all-star polar align routine on your CGEM, you generally no longer need to adjust the latitude unless you're imaging with the C8, in which a drift alignment is almost mandatory. This of course, assumes your mount is perfectly level - get a good spirit level, not the $2 China ones. Basically if the spirit level shows tilt when placed on the shop's floor, or different levels show different readings, you know you have a problem
I suspect if you're imaging through your ST80, drift alignment may not be that necessary.(suspicion only)

couldn't run ASPA. will practice that on top of NUHS tower one day

Condo is south facing with alot of obstructions.

not at drift alignment yet..... let me practice the basics first...

orly_andico · Post by **orly_andico** » Thu Aug 18, 2011 5:53 pm

i bought this coleman magnetic compass at carrefour that has a pop-up top with a wire sight (1/2 of a reticle). for some reason i still can't aim north properly with it.

i have found a pretty foolproof way of aiming north though:

when you set up the CGEM in home position, turn it on and it will slew to the first alignment star. now, adjust your alt and az screws so that the star is centered (i.e. do not use the hand pad). and.. that's it. good enough for visual, but you still need to drift-align if you want to image.

cloud_cover · Post by **cloud_cover** » Thu Aug 18, 2011 7:06 pm

I compass align the way I've always done it in the army: Use a Silva compass, sight on a distant object then rotate my mount on the tripod until the scope is pointing where it should be (west, in my case, a specific requirment of the SXD setup) .
Silva compasses are $10-$15 at Beach Road. I don't bother with the lensatic compasses because the lenses are of such poor quality that they are useless in the dark (duh! China made...) and true prismatics are expensive.
Generally in my setup kit I almost always have my Silva compass and my spirit level. It helps the Silva also has bright dots on the needle indicating N

However, when just doing grab-and-go visual (on the alt-az) I just immediately slew to the brightest target (moon, if up) then rotate the mount. Easy peasy. Fine adjustments thereafter done on an agreeable star.

shirox · Post by **shirox** » Thu Aug 18, 2011 7:08 pm

buy a silva compass