I set the PST up on the CG5 today with the intention of trying the DMK out to see if I could achieve focus. There was patchy cloud around so that slowed down progress a bit, but eventually it came together. I had to use the lens out of my 2x barlow in the node piece of the DMK to achieve focus (and no UV/IR filter).
These images were captured with the following settings:
Brightness =0; Gain = 374; Exposure = 1/370s; Gamma = 26, FPS =60.
The mosaic was assembled, cropped, colourised and saved for the web in PS CS3 using photomerge. The other two were stacked and wavelets applied in Registax V4, then colourised and saved for the web in PS CS3.
Lots of dust bunnies! I tried Mike's Q-tip and distilled water trick - unsuccessfully... I'll have to invest in an arctic butterfly or something! oh, and I found the PST was a little light for the CG5 counterweight by itself so I ended up with a 2lb lump hammer taped to the counterweight shaft!
Nice first light Al, looks like focus is slightly off and man look at all that dust!
I have always cleaned my webcams (ToUcam/DMK) with the q-tip/distilled water and it works every time. Sometimes a spot has been left that i've had to go back and do again, but it eventually works. I hope those spots aren't under the glass cover!
Nah, there just sunspots starting to form, we are moving towards a solar maximum again remember
Gotta luv dat arctic butterfly
Yep I'd say the focus is a tad soft as well. It's not easy focusing the PST with the laptop. All that damn sunlight makes it so challenging. I tried to do it under a shade hood but I need to see the image and focus at the same time to get close and my arms aren't long enough. I even bought an Orion motorized focuser for mine, but I'm yet to work out how to mount it
Nah, there just sunspots starting to form, we are moving towards a solar maximum again remember
Gotta luv dat arctic butterfly
Yep I'd say the focus is a tad soft as well. It's not easy focusing the PST with the laptop. All that damn sunlight makes it so challenging. I tried to do it under a shade hood but I need to see the image and focus at the same time to get close and my arms aren't long enough. I even bought an Orion motorized focuser for mine, but I'm yet to work out how to mount it
Yeah, focusing the PST is a challenge alright. I was about the best set up that I've managed today. I had the lappy in the light control hutch and the shade hood over the lot with the focuser in easy reach, the scope on the CG5 so it was tracking... still didn't nail the focus. But the main aim of the exercise was to prove I could get focus. While I couldn't without the barlow lens, I had plenty of adjustment both sides of focus with the lens, so it's just lack of skill/perseverance on my part. I'll have to bust those dust bunnies though!
Can you post a pic of your adapter Al. My adapter had a small shoulder on it that butted up against the body of the camera. Once I ground that off with the Dremil I was able to get the camera another 5 mm closer to the pst and got focus np.
I had a 2 lb lump hammer taped to the counterweight shaft with insulation tape. It will require a more permanent solution... either piggy back it on the C8 and use the normal counterweights or get a smaller counterweight.
Can you post a pic of your adapter Al. My adapter had a small shoulder on it that butted up against the body of the camera. Once I ground that off with the Dremil I was able to get the camera another 5 mm closer to the pst and got focus np.
I'll try to remember to get a shot tomorrow, Paul!
1. The first photo shows the 1.25" EP adapter is 30mm to the shoulder.
2. The second shows it's about 33.5mm to the body of the DMK.
3. The third shows the depth of the EP holder on th PST is only 29.5mm.
4. The last one shows the DMK in the PST and confirms there is about a 0.5mm gap between the shoulder and the top of the PST EP holder.
So it seems clear, to get the extra travel inwards I'll have to cut the front off the adapter and take the shoulder off as well. So before I launch into this I might have a look around and see if I can pick up another C mount EP adapter (I might just snag a short one, or at least I'll have a spare if I destroy the filter thread in the process).
Paul, maybe these posts should be moved to a new thread in Equipment Discussions or something rather than just deleted?
Al.
Last edited by sheeny; 30-03-2008 at 10:35 AM.
Reason: afterthought
Al that looks like exactly the same adapter I have. I bought mine here. I know you have measured them but try it, what have you go to lose. Saves buying another adapter and removing the shoulder won't affect how the adapter works. That is of course unless they have changed the height of the PST 1.25" sleeve. I'll check mine.
Ok just checked. My C-1.25" adapter is considerably shorter than yours. Sorry about that. From the waist to the nose of the adapter mine would only be half your length.
No worries. It's times like these a little lathe would be ideal! I'll have a go at it anyway, and get another adapter if I need it. I have feeler out in IceTrades already...
At first I thought I'd do it by hand with a file and hacksaw, but after the first slip of the file highlighted the risk of damaging the C thread, I figured it was better to get the bench grinder out of the packing and set it up. Much more controllable and quicker. (Just don't anyone mention to Lyn that I had it clamped to the outdoor table setting to use it).
I had to grind 4mm off the front of the adapter. The heat from grinding ruined the anodised finish on the node piece obviously. And I managed to recover the eyepiece thread after much fiddling. It feels a bit rough as a filter screws in but at least it works.
The first image shows the camera fitted to the PST. It goes right in now, but I noticed that the EP locking screw lifts the camera about 0.5mm wen tightened - it must be on the edge of the safety groove.
The other shot shows the modified adapter.
I'd like to slip out and try it out now (the sun is shining) but I have a book launch to go to this arvo...
Woo Hoo, now your cookin'. When you work out which way around the camera is supposed to go to get the image the right way up, just take a bit of a notch out of the shoulder of the safety groove.
oh, and I found the PST was a little light for the CG5 counterweight by itself so I ended up with a 2lb lump hammer taped to the counterweight shaft!
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