LMC, first image with "new" mount

[graphworlok (James)]

Took a good 5 months or so between buying a second hand HEQ5 and getting a picture. (Had to tap a hole as the locating nub on the mount had been broken off, and had to cad up and print a dovetail)

EOS40D, 200mm SMC Takumar telephoto, HEQ5.

Now i'm getting unhappy with my glass and the amount of chromatic abberation i see..

http://somepicturesof.space/Tarantula.png

It's a world of difference from the EQ3 i've been using for 8 years or so..

[alpal]

Hi James,
what have you done with the processing?
The stars are dark in their centers.
Also it looks like your mount was not level as the stars at the top are round
but the stars at the bottom are egg shaped.
How were you guiding it?
How did you focus it?

cheers
Allan

[graphworlok (James)]

alpal,

Focus by cranking the lense to the "infinity" stop (I'll be printing up a focus mask when i get a round tuit, as i do believe it's a smidge off)

No guiding - 65 second exposures. Once i figure out the controller pinout, i'll make up an arduino based PC interface that will let me guide with PHD

Mount should be level, but i'll check that again - i've got three pavers cemented into the ground with holes drilled for the tripod feet to sit in, and i almost certainly didn't check the level before imaging (I levelled it once when it was daytime and cloudy) - i was in a rush after doing things like hunting down a bolt to cut to the right length to fasten the camera to the DIY dovetail plate.

Processing was reasonably quick in DSS - a few flats and darks and some stretching.

There was also essentially no drift aligning - i aligned the camera via eyeball on the EQ head, pointed it towards the SCP, and took some "star trail" images, and adjusted the mount until the stars were circling the "middle" of the sensor

Crude crude crude, i know - but i'd been waiting for quite some time to take some images!, and didn't want to waste the night drift aligning.

[Atmos (Colin)]

Not a bad start James, feels good to get back out under the stars

My biggest suggestion would be to spend the extra minute getting focus spot on, the vast majority of lens' don't have a hard infinity stop meaning infinity focus is back a little. I didn't realise this for the first few months with my 24-120mm lens

[alpal]

Originally Posted by graphworlok

alpal,

Focus by cranking the lense to the "infinity" stop (I'll be printing up a focus mask when i get a round tuit, as i do believe it's a smidge off)

No guiding - 65 second exposures. Once i figure out the controller pinout, i'll make up an arduino based PC interface that will let me guide with PHD

Mount should be level, but i'll check that again - i've got three pavers cemented into the ground with holes drilled for the tripod feet to sit in, and i almost certainly didn't check the level before imaging (I levelled it once when it was daytime and cloudy) - i was in a rush after doing things like hunting down a bolt to cut to the right length to fasten the camera to the DIY dovetail plate.

Processing was reasonably quick in DSS - a few flats and darks and some stretching.

There was also essentially no drift aligning - i aligned the camera via eyeball on the EQ head, pointed it towards the SCP, and took some "star trail" images, and adjusted the mount until the stars were circling the "middle" of the sensor

Crude crude crude, i know - but i'd been waiting for quite some time to take some images!, and didn't want to waste the night drift aligning.

Hi James,
I level my mount with a spirit level -
which doesn't hold well on soft ground - you need concrete.

A drift align to find exact South should be a 10 minute job if
you do say a 40 second exposure & with the mount on X1 drive it in RA
East for 20 seconds & West for 20 seconds.
(while pointing the camera North at about 45 degrees)
If you get stars as a V shape you're out -
adjust one way or the other to turn the V into a straight line
for the next " iterative method" exposure.

I suppose a mask will help you find focus.

cheers
Allan