here's a recent image with Houghys cooled camera on my WO 110mm refractor fitted with a CLS filter and a Baader Coma Corrector (yes you heard correct - this gives less coma than the WO 0.8x reducer/flattener vIII )
Great image Paul, shows the advantage of having a cooled and modded DSLR. Can you tell us more about using the MPCC on a refractor? I'm waiting for a WO 0.8x reducer/flattener, but if the MPCC does the job it may be a wiser purchase in the longer term.
Great image Paul, shows the advantage of having a cooled and modded DSLR. Can you tell us more about using the MPCC on a refractor? I'm waiting for a WO 0.8x reducer/flattener, but if the MPCC does the job it may be a wiser purchase in the longer term.
Cheers,
Rob
G'day Rob,
I'm not sure how much I can tell u about using the MPCC on the refractor except that it appears to work better than the WO Field Reducer/Flattener Version III that I bought with the 'scope.
I did need to use a tele-extender in combination with the MPCC to get focus.
I stopped using the Wo flattener cause;
1. was not happy as it did not give me a flat field,
2. it exhibited a fair degree of coma,
3. stars around edges of image were stigmatic (i think that's the correct description - the stars look like a Cross + rather than a Round star).
So yes, the MPCC actually works and seems to give better images! By "better" I mean flatter!
nice image Paul, may l ask why a CLS filter? l thought this would have dulled the image somewhat.
g'day Mick,
Houghy loaned me the CLS filter so I thought I would give it a go - that's why I am using it - I think the filter works well for suppressing light pollution.
Lovely shot mate. The CLS is a more "gentle" filter, suppressing the brightest light pollution bands but letting most other light through, which is idial here as Pauls place is somewhat darker then mine and doesnt really need a very severe filter, particularily to the west when he was imaging the horsehead
Great composing and colour balance there!
Gee the coma corrector sure worka too doiesnt it, no coma there at all
Scott
I'm not sure how much I can tell u about using the MPCC on the refractor except that it appears to work better than the WO Field Reducer/Flattener Version III that I bought with the 'scope.
regards
G'day Paul,
Hmm, that's interesting. Just took delivery of a WO P-Flat3 on Friday, and my first impression is, it over-corrects an ED80. Stars in the corners are crosses.
Attached image is 14x6-minute subs, 400d unmodded, ED80+P-Flat3.
Hmm, that's interesting. Just took delivery of a WO P-Flat3 on Friday, and my first impression is, it over-corrects an ED80. Stars in the corners are crosses.
Attached image is 14x6-minute subs, 400d unmodded, ED80+P-Flat3.
Cheers,
Rob
Hello Rob,
Yep that's exactly right - the stars near outer edges appear like crosses - and that was a disappointment to me personally - i was expecting a nice flat field of stars. See http://www.skylab.com.au/pmsa/Seagull_Nebula.html - you can see the distorted cross shaped stars.
I think that focus position has a little to do with how badly the crosses appear? at the cost of less than perfect focus at centre image.
The Baader Coma Corrector doesn't give crosses but the stars still appear somewhat comatised near edges.
With my 6 inch cometracker, it has a field thats not flat (being a schmidt Newtonian, schmidts have curved fields) , the coma corrector helps but not 100%. Theres very little coma just a field thats not flat, as if I rack focuser in, the centre becomes blurred and stars at the edge sharp. I try to hedge the bet and get centre a tiny bit out, edge tiny bit out and stars 1/2 way out perfect.
Scott
Beautiful soft colours. Very natural, It seems the CLS is ideal for bringing this out. Just a coment on the Shmidt Newtonian, I use exactly the same focusing trick to balance the focus across the field. Happily, my DSI II has a small enough chip, (greatful for small favours so to speak), so that its not such a problem in photos.
)
