Trapezium Resolved, well sort of.

[tilbrook@rbe.ne (Justin Tilbrook)]

Hi,

I apologize in advance for the crappy stars.

I recently purchased an old 8" Meade Schmidt cassegrain off an IIS member and wanted to give it a whirl.

Apart from the obvious mirror tilt, slight drift in guiding was problem at the 2032 mm F/L using only the orion mini guider.

Still, I had a lot of fun playing with it.

15 x 2 minute subs and 6 x 30 second at ISO 400.

Cheers,

Justin.

[TimberLand (Justin)]

I like that this was just a play session. Ten years ago that would be at the back pages of Sky and Telescope, how technology has improved.

I have noted that my setup has really improved over the years by the type of hand me down guide camera from the Philips webcam to DSI colour and now the DSI Pro II. Soon to be the DSI Pro III.

They migrate from the main imager, to the guider, to the electronic finderscope, to all sky cloud camera.

I imagine your road to round stars has a similar track. Big focal lengths are increased difficulty (trust me I have been dealing with my beasty for a while and only now getting reasonable results) but the number of targets goes up as well.

Justin

[tilbrook@rbe.ne (Justin Tilbrook)]

Originally Posted by TimberLand

I like that this was just a play session. Ten years ago that would be at the back pages of Sky and Telescope, how technology has improved.

I have noted that my setup has really improved over the years by the type of hand me down guide camera from the Philips webcam to DSI colour and now the DSI Pro II. Soon to be the DSI Pro III.

They migrate from the main imager, to the guider, to the electronic finderscope, to all sky cloud camera.

I imagine your road to round stars has a similar track. Big focal lengths are increased difficulty (trust me I have been dealing with my beasty for a while and only now getting reasonable results) but the number of targets goes up as well.

Justin

Thanks Justin!

Yep, playing with long focal lengths is a different ball game!
Everything has to be spot with accurate polar alignment.
It's certainly given me a kick in the pants to align my mount better.
I mainly purchased the 8" schmidt cassegrain for visual planet work, but may upgrade to a Crayford focuser so I can image some brighter planetary neb's and some close ups on others.

I can only imagine the battle you had with your 16"

Thanks for your input.

Cheers,

Justin.

[Merlin66 (Ken)]

Justin,
I used 8", 10" and 12" Meade Lx200 for spectroscopy for a few years.
Getting and guiding a target star on a 25 micron slit gap was challenging (!!)
I did find the simple threaded rod and spring version of the mirror holding clamp worked pretty well and certainly stopped any mirror "flop"
The mirror needs to be run up and down the baffle tube every week or so to spread the grease/ glue and minimise mirror flop.
You still had slight mirror "slop" while reversing focus direction, but with experience and practice that could be minimised...
It's only because I could relocate my 12" OTA (>17Kg) onto the NEQ6 that I sold all the Meades and went for a C11.

[tilbrook@rbe.ne (Justin Tilbrook)]

Originally Posted by Merlin66

Justin,
I used 8", 10" and 12" Meade Lx200 for spectroscopy for a few years.
Getting and guiding a target star on a 25 micron slit gap was challenging (!!)
I did find the simple threaded rod and spring version of the mirror holding clamp worked pretty well and certainly stopped any mirror "flop"
The mirror needs to be run up and down the baffle tube every week or so to spread the grease/ glue and minimise mirror flop.
You still had slight mirror "slop" while reversing focus direction, but with experience and practice that could be minimised...
It's only because I could relocate my 12" OTA (>17Kg) onto the NEQ6 that I sold all the Meades and went for a C11.

Thanks for the advice Ken!

Is there a youtube tutorial or something similar that shows the mod?

Cheers,

Justin.

[Merlin66 (Ken)]

Justin,
the original design was up on the MAPUG site...
http://thadlabs.com/MAPUG/

[tilbrook@rbe.ne (Justin Tilbrook)]

Originally Posted by Merlin66

Justin,
the original design was up on the MAPUG site...
http://thadlabs.com/MAPUG/

Thanks Ken!

Just checked out this site, and there are quite a few option for improving mirror flop and focusing.

Cheers,

Justin.