Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Jul 8, 2020 11:55:27 GMT
This is IC 2948 Running Chicken ,Esprit 80,Apex focal reducer, optolong l-enhance filter 6 x 59sec and 5 x 40 secs without the filter cheers Paul
|
|
|
IC 2948
Jul 8, 2020 12:23:11 GMT
via mobile
Post by davy on Jul 8, 2020 12:23:11 GMT
Looking good
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Jul 8, 2020 15:22:59 GMT
The filter made a big difference for IC 2948, but the exposure time needed to be a minute. So did ngc 3372, eta carina .This was 6 x 50 secs,zwo 183 . A very easy scope to use.You will love it Davy.Wasnt much good for galaxies ,the Centaurus A and ngc 4945 which barely showed up with filter. Need the 290 on the Rasa without a filter for those objects Here is the single 30 sec shot from a week ago with the same gear. cheers Paul
|
|
|
IC 2948
Jul 8, 2020 20:05:06 GMT
via mobile
Post by davy on Jul 8, 2020 20:05:06 GMT
Lot of cloud and rain here Paul,, have my two scopes on the twin saddle, and hope to get some decent weather soon to test,,
Here is a question,, see if I'm. On the right track with my thinking 🤔
I was in first light optics website and checking out fov with the cdc app,, to see how the zwo 178 mc and Canon 600d compare, ect I put in Canon 600d and a 0.63 focal reducer and it showed the the box around andromeda,, and it looked great. Out of curiosity I put in a Canon 5d mk2 full frame camera and it was,, very near same fov as the 0.63 focal reducer,,
It's all down to capturing the photons,, and the full frame camera will collect more light,, how does this equate to the f number,, if the focal reducer takes the scope from F5 to f3.2,, What does the full frame camera do to the f number,, I'm thinking it has to reduce it,, Have I got it wrong 🤔😁😅
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Jul 8, 2020 22:17:53 GMT
gidday Davy The scope and the focal reducer will get you the F number.Independent of the sensor size. The sensor size of the camera divided by the focal length of scope and focal reducer will get you the FOV. The scope collects the light. How the light is delivered to the camera sensor starts to get complex and might be better explained by some experts out there. The resolution is determined by the pixel size divided by focal length of the scope plus the focal reducer. Then we start getting into oversampling and undersampling . I am not sure how significant oversampling is for VA . It seems to matter to astrophotographers. This image I posted the other day of Carina nebula with the zwo 294 on the Esprit 80 plus the Apex reducer was grossly undersampled at 3.7"/pixel. It was very soft compared to the zwo 183. I am not sure if that was the only factor or not, but the 294 needs longer focal lengths to get the right resolution. I am not sure what size pixels you have on the dslr. I am going to start using the 8" f/4 newt with the zwo 294 because of its 800 focal length. The 294 is my favorite camera but has not been used much because the Rasa is 400 fl and so is the Esprit 80.and the 8" lx90 sct used at 800 to 1200 fl gives me lousy images. hope that rain stops Davy Arent you guys in summertime? cheers Paul
|
|
|
Post by davy on Jul 9, 2020 13:07:02 GMT
Thing we had our yearly intake of the sun for week,, not raining today though
|
|