Preparing for Venus Transit

[PhilfromOz]

Hi all,
I started preparing for the Venus transit today, by trying out an Orion Solar Filter, recently bought from Bintel, on my G8/Gemini Mount and Televue 76 OTA. Effectively this was first (day)light for this configuration.

NB I smiled to myself, when I almost set up the Guiding Scope as well, and then realised the futility of that… Anyway, finding the Sun in the Flip Mirror’s eyepiece, was more of a challenge than I expected as the Telrad was of no use. However, once located and centred, I was happy that the Solar Filter worked a treat.

OK, now for some imaging. Flipped the mirror, set the EFW filter to Clear (Luminance) and took several (6 x 30) series of images at 1/1,000 second (Atik 213e minimum exposure) doing minor (random) focusing adjustments between each set.

Solving the problems (to hopefully make the 6th June smoother):
a) Finding the Sun (both initially and during the day) – Televue acknowledge this may be an issue and offer their “Sol-Searcher” product. I made up an equivalent from various bits in the garage (see image) and tested it out later in the afternoon




b) Laptop screen display – I found it a bit difficult to see the image quality of the test series. I must remember to take a cover / box to overcome this

c) Focussing of Images – one set was nice and sharp edged, the rest were blurry by varying degrees at the edges. Presumably on the 6th, I can just do some trial & error imaging of the Sun before the transit, to set the best focus, or arrive early and use visible night sky objects for this. Any suggestions are welcome on the best approach…

d) CCD Images
- Is there any point in taking LRGB sets (like with Nebula)? As above, with the test images I have assumed I would use the Clear Filter in the EFW
- What causes the white “bleeding” area below the Sun?
- There is a tiny fleck in the top left hand quarter. Is this a hot pixel effect?
- Should I expect to see any detail in the image?


Appreciate suggestions

Phil
NB This is my first post with images, so hope they work - Should be 3

[DJT (David)]

Hi Phil

I was also messing around with the sun today, ahead of the transit. But I got a group of sunspots on my image which you should have also got.

This was shot at 1/100 on ISO 100 using a Canon 30D DSLR. Single image. Added "warm" filter in CS6

http://i1154.photobucket.com/albums/...22c_CLS_V1.png

[barx1963 (Malcolm)]

I would have expected to see sunspots ATM. I would suggest that the shots are overexposed. On my setup I have to drop the gain down a fair bit and I was imaging at 1/10,000 with a DMK on a SMII scope.

Malcolm

[PhilfromOz]

Hi all,
I sorted out my solar imaging issues, predominantly through more accurate focussing (Using the sunspots to best advantage) and reducing aperture size (via cardborard rings of various diameters, until I had a match).

Viewing the actual Transit at Kenshurst NSW was an experience, with the clouds, wind and rain.... But staying for the full duration and imaging in the small cloud breaks paid dividends.

Phil