M8/M20 - Canon 350D/Canon 70-200 F2.8L

[Tilt]

1st attempt.

17 shots around 1min each, unmodded 350D, Canon 70-200mm F2.8 L (@ 200mm), 5km from Canberra city, tracked but not guided on a EQ6.

Combined in Deep Sky Stacker, then processed in PixInsight to subtract an artificial dark frame and wavelets. Other processing in the GIMP.

[Bloodbean]

Looks like a great start! What ISO setting did you use for this?

Troy

[Tilt]

Used ISO 800 @ f2.8, I'm not sure if its too high? Plus the stars look a bit strange here and there... Tracking error, mirror slap?

[Robert_T]

I like this, not often I see both M8 and M20 in the same shot.:)

That's a serious bit of glass 70-200 F2.8...one of the white lenses?

[Tilt]

Yep it sure is. I bought it around a year ago for terrestrial photography, then after a couple of viewing sessions with David (Prickly) and his Vixen/EQ6 set up we got the idea of piggybacking the 350D/70-200 f2.8 on the scope. Had our first try of it a few nights ago and it seemed like a lot of fun.

[Ric]

That's a great looking widefield Tilt, very sharp and lots of natural colour.

A fine first attempt.

[Tamtarn]

Great first attempt Tilt. Keep them coming :thumbsup:

[Ian Robinson]

Can't wait to get my 40D and 70-200mm f/2.8 L IS .

How have you mounted the lens + camera on the EQ6 ?
I am thinking of an arrangement that used both the lens mount and the camera mount, to keep lens and camera as rigid as possible.

Also wondering if a teleconverter (1.4x L style) is worth getting ?

[AlexN]

excellent image with 2 of my favorite objects! Nice focus too, looks near on perfect... now mod that 350D :D

Ian: I too can not wait to get a 70-200 f/2.8L for my canon (which Im getting friday, modding hopefully by next week..)
I will say this on Teleconverters. Whilst they do increase your focal length by the amount specified... they will also lower your max aperture. I cant remember the exact amount, but I think its something like with a 2x teleconverter a 2.8 becomes 5.3~5.6 not exactly sure..

Be sure to remember that on a 1.6 crop camera (300/350/400/450/10/20/30/40 D series cameras) the 70-200 lens is effectively a 112-320 or there abouts... the extra focal length provided by a 1.4 or 2x TC is nice.. but relatively unnecessary

[Ian Robinson]

If I remember how they work , a 1.4x will add one extra stop , or double the exposure required.

I don't mind that as sometimes I may want to have a tighter view of something (like a comet , a particularly nice nebula or cluster , a person , a bit of scenary somewhere ). And at only about $300 ish extra , that bit extra versatility seems handy, beats lugging about another zoom.

[Alchemy]

As previously said, a fine first attempt, lets see some more:thumbsup:

[Tilt]

Thanks for all the :thumbsup:, David and I just took a peek into the void that is Imaging, how deep does it go?

Ok guys, here are a couple more taken on the same night, with the same set up.

Antares Region, only 4 mins of data before the batteries gave up :lol: Plus we were off with the alignment a little so most of the interesting stuff is out of the frame. There is always next time.

NGC3532 1 min x 10.

[Prickly]

Hi Ian,

You asked how we mounted the lens - we used a fairly heavy duty manfrotto ball and socket screwed into a bit of wood. The wood was screwed this into the top of the tube rings. Its a bit rough and ready but fairly low tech and it works. It seemed quite well suited to Michael's lens which sat pretty securely.

I have had a C90 mounted on the platform with the ball and socket as an autoguider when imaging through the main refractor and that worked ok too.

Cheers,
David

[AlexN]

Question:


Answer: He He He He Heeee... (insert menacing grin here..) From what I've gathered after my few weeks of falling and not hitting the bottom.. It goes DEEEEP!!!

Nice new pics too!

[Screwdriverone]

What Alex said. :evil2:

Chris

[dugnsuz]

Hi Ian,
You may not need to mount both lens and camera.
As I recall the f2.8 comes with a sturdy tripod ring adapter.
I attach my f4 lens/tripod ring to the mount with this handy dovetail bar...
https://www.bintelshop.com.au/Images/Stock/7734X.jpg
(about $30 from bintel)

Combination is rock solid.

I use the EF 1.4x extender with my 70-200mm f4L and it's great.
This Eta pic was taken at 280mm FL, with lens + extender...
http://s231.photobucket.com/albums/ee208/dugnsuz2/?action=view&current=ETA-POST-MOD.jpg
Stars are still points out to the edges of the frame, gotta love that!!!!:P
Drops f ratio one stop, but I wouldn't say that you needed to double exposure times though.
1.4x gets a good rep, but the 2x isn't as highly regarded I've read.
Cheers
Doug:thumbsup:

[Tilt]

Yes the F2.8L comes with the tripod mount ring.

The dovetail bar is a great option for mounting the camera Doug :thumbsup:

I'd like to eventually get the 1.4x teleconverter to go with the 70-200, as Doug mentioned it only drops it by one f-stop, I believe the 2x version reduces the effective aperture by 2 stops.

David recently revealed to me that he has a Tamron F2.8 with a fixed focal length of 300mm, might put the Canon back into the camera bag for the next imaging session.

[Prickly]

Hi Doug,

As Michael says - thanks for the idea with the dovetail plate. What a handy piece of kit! I can see that being helpful for the 300 f2.8.

Oh dear - more to add to the wish list!

Cheers
David

[dugnsuz]

No Worries,
Luckily it's not too expensive!
I bought one of the generic "for Canon" tripod rings off ebay and found that the screw on the dovetail bar was too long and that the tripod ring was loose. A couple of small washers on the underside of the dovetail bar rectified this and the bar still fit snugly in the dovetail...does that make sense to you!!:shrug::lol:

[Prickly]

Gotcha, thanks Doug and not to expensive for sure.

I think its the rest of the wish list that's the real problem! ;)

Cheers
David