I got up at 1am to image Mars yesterday morning. Unfortunately I didn't leave the scope out all night to cooldown, so the first 45 minutes of the session produced no worthwhile results, as the tube currents in the OTA meant the image was wobbling about all over the place.
By about 2am the scope had settled and I was getting more detail. Here's my best effort from the night.
Unfortunately the colour is a little off, a bit too yellow for my liking, but i'm pleased not to have any hard edge artifacts and the SPC is quite well defined for a change.
Also as an exercise to show how much closer Mars is to us now than it was just over 2 months ago, i've included on the attachment my very first Mars image this apparition (back on 29/07/2005) showing the same face, when it was only 11.05 arcsecs in diameter. It's now a whopping 18.39 arcsecs and will still grow more over the next month.
I'm going to get a 5x powermate, very soon. Mars oppositions only come around once every 2.5 years so I can't miss out on an opportunity to get an image of Mars as big as it can be. Also, Mars oppositions will be smaller for the next 10 years as well, so there's no time like the present!
do tube currents move the image or fluxuate the image bigger / smaller etc?
From my experience, the tube currents can give the appearance of bad seeing. ie Distorting the shape of the image and making it wobble about as well.
If i'm planning to get up early in the morning for some imaging, I leave the scope out (dust cap off) overnight under the pergola so that it's all cooled down and is at ambient temperature.
I did that overnight last night, with a view to imaging Saturn this morning, but was foiled by clouds.
i have found thru bink and smacker that the phillips toucam has been recording at 15fps even if i change it to 5 or 10. I will give k3ccd a go i think so i can control it better.
so if seeing is good, go to 5fps, if seeing is bad, drop it back to 15fps or 20fps?
I only ever use 5 or 10. Any higher than that, and it has to compress your raw data even more to shove it down the USB1 pipe fast enough.
If seeing is great (7-8/10 or higher), I use 5fps because it compresses the data the least. You want good quality raw frames when the seeing is at its best.
If seeing is anything other than great, I use 10fps because you can get more frames where you might capture moments of good seeing, without too much extra loss due to compression.
If the USB2 ToUcam comes out like it's supposed to, then we'll be able to capture at 30fps with no compression - which is what you want. The most frames in the shortest time.
Nice images Mike, but yes a weird sorta colour.
Have you tried E/P projection, assuming you can sort the necessary mechanics out? I would recommend it, especially if the 5x is only really used for Mars.
Gary, Mikes setup is very similiar to mine i think, ie 10" dob, crayford focusser. I am yet to find eyepiece projection working with my setup - can't focus. Reading on the Televue website, it seems epp is a dying setup???
Mike/Davo,
for E/P projection I simply screw the 1.25" - ToUcam adaptor onto the rear of one of my orthos. The weird thing about the Zeiss orthos is that the circular ring at the eye end unscrews leaving a thread. this thread is used to screw filters (either singly or as a turret) onto the end of the eyepiece. The thread is about 24mm. In a quirk of fate, we (Robbie and I) got a heap of 1.25" adaptors made locally when we first got a ToUcam. The central hole was just a shade under 24mm, and I got the appropriate 24mm thread cut to allow this feature. I use it all the time now.
As for focus, if the eyepiece comes to focus it will also allow E/P projection, or will in my case.
As for the most used focal lengths, I find that the 5x Powermate is approximated by the O-6mm, and the 2.5x by around the O-12.5 or O-16mm. Of course if the seeing isn't too flash I can use the O-8mm, or O-10mm.
Would a picture help?
Gary
I have tried the eyepiece at the top, bottom, without the middle barrel and to no avail.
Basically i can't work how this item can work with any eyepiece in my scope: http://www.telescopes-astronomy.com....d_adapter1.jpg
Apparently the supplier sells for refractors and reckons they work, but no go with my reflector! He was very helpful, but no luck!
Top work again Mike, look forward to see how the 5x powermate goes
