Some wide field images with my new 35mm lens.....

[geoflewis]

After humming and hawing for years, I finally pulled the trigger on a 35mm lens for my old astro modified Canon 600D. I wanted something portable for 'grab and go' widefield full constellation and MW shots. My 600D has barely been used in the past 5 years since I moved over to mono CCD imaging, in fact I sold the camera a few years ago, then bought it back a year later and still have not been using it. The lens I purchased was 2nd hand off mpb.com, and is the EF F2 35mm IS USM. It arrived in excellent condition as advertised.

I had a couple of hours clear sky last night between 11pm and 1am, so quickly set up my Star Adventurer Pro mount with the camera and lens. I only did a quick and dirty polar alignment, so was pleasantly surprised to see that I could get round stars up to 4 min exposures (I didn't try anything longer). I experimented with the different exposures, F2 through F4 and ISO 800 and 1600. F4 certainly yields better star shapes than F2 and its a bit of a crap shoot between ISO 800 and 1600.

Here are a couple of processed images. Both images are single exposures, Orion 3m at ISO800/F4 and the MW shot 2m at ISO1600/F4. The Orion image is cropped, mostly the remove bad LP gradient and blurred tree tops (remants still showing) towards the horizon.

 

 

Not bad for single exposures and definitely something to do rather than hours of long exposures with the CCD as and when (or even if) the skies allow.....

I had a lot fun popping over different regions of the sky and then took a half a doz 2m subs of each of the Taurus and Auriga regions. These were stacked without any calibration, stretched and put together a 2 panel  mosaic in MS ICE...

 

Bands of cloud started drifting through Taurus and shortly after the entire region was lost to clouds.

 

The images off the modified 600D all turn out very red, which makes processing them something of a challenge, so I'm going to have to learn how to best process these wide FOV images. That said I can see me doing a lot more of this, either instead of mono CCD imaging, or at the same time when the gear in my observatory is working on deeper DSOs.

 

Adding to the rig, I have today taken delivery of a couple of items to help automate the imaging with this get up and go configuration. They are:

• a HitecAstro Single Channel Dual Port Dew Controller (https://www.modernastronomy.com/shop/accessories/dew-control/single-channel-dual-port-dew-controller/) so that I can wrap an old short dew strap around the lens, which I'll run off a Tracer LION battery that I've had for several years, but hardly ever use, and
• a Hahnel Captur Timer Kit (https://www.wexphotovideo.com/hahnel-captur-timer-kit-canon-1610616/) so that I can run sequences of longer exposures without the need for me to stand by the rig and fire the shutter every couple of minutes with my remote control.

It will be interesting to find out how automated these 2 additions allow the Star Adventurer Pro, plus camera and lens to become, even though currently I have no plan to try guiding the mount and will capture to the camera's SD card. My wish is the keep the rig as self contained as possible, so no laptop, etc.

Thanks for looking.

Edited February 5, 2021 by geoflewis
updated the Orion image

[Gina]

Nice ones Geof!  👍👍👍

[geoflewis]

2 hours ago, Gina said:

Nice ones Geof!  👍👍👍

Thanks Gina

[Bob-c]

Well done Geof, something different to play at.

 

Bob.

[Padraic M]

Oh that looks like fun! Must add to my long list of must-buys!

[geoflewis]

3 hours ago, Bob-c said:

Well done Geof, something different to play at.

 

Bob.

 

53 minutes ago, Padraic M said:

Oh that looks like fun! Must add to my long list of must-buys!

Thanks both, I've wanted to try some wide field imaging for a long time, but didn't have the gear to do it. I bought the SA Pro mount last year when Comet Neowise came around, but I was late to that game and then clouds ruined my chances, so it became something else collecting dust. However, I always knew that I was going to go down this path sometime, so Neowise was just the prod to make the first steps. I now have the lens, timed remote shutter release and a dew strap for the lens, so all I need now are some clear skys to get a long run at it..... 🤞

[geoflewis]

I had another somewhat interupted session shooting Orion with my Canon 600D+35mm lens on the SA mount last night. I still don't have as much data as I'd like as I was dodging clouds and snow flurries yesterday evening - somewhat unsuccessfully....!! I set the camera running last night under a clear sky and came indoors to keep warm. When I went back out 20 mins later everything was covered in snow, so I had to start over. but even then I was only getting 10-15m sessions between clouds and Orion started to set into trees, so I had to give up. Anyway, here is what I've managed to extract from the 35mins or so of data that I did manage to collect. I really need a much longer session to be able to push the stretch harder, but I feel as if I'm gradually getting there......

 

Orion was getting so low into the horizon LP and tree tops by the time I finished collecting data, that I've had to crop the lower edge pretty heavily, but I can just detect a hint of the Witch Head Nebula above the LP in the lower right corner.

Thanks for looking.

Edited February 11, 2021 by geoflewis
Revised image to reduce LP gradient in bottom right corner

[Gina]

Nice start 👍

[Astrobdlbug]

Seriously wide fields - love it.

I though working with 135mm gave a decent wide field with ASI1600 - but a 35mm takes it to a different level - dont think I am too wide of the mark to say the sensor in your 600D and ASI1600 are similar as I imagd with 600D when I started imaging.

I have similar issues with Orion this time of year dissapearing into trees to by South West / West.

 

Will be great if you can add more to the Orion widefield before it is enveloped by the LP .

 

Look forward to the finished article,

Bryan

[peter shah]

Great work Geof, That is a superb FOV 

[geoflewis]

16 hours ago, Gina said:

Nice start 👍

11 hours ago, Astrobdlbug said:

Seriously wide fields - love it.

I though working with 135mm gave a decent wide field with ASI1600 - but a 35mm takes it to a different level - dont think I am too wide of the mark to say the sensor in your 600D and ASI1600 are similar as I imagd with 600D when I started imaging.

I have similar issues with Orion this time of year dissapearing into trees to by South West / West.

 

Will be great if you can add more to the Orion widefield before it is enveloped by the LP .

 

Look forward to the finished article,

Bryan

1 hour ago, peter shah said:

Great work Geof, That is a superb FOV 

 

Thanks all. One thing I've learned with this 35mm lens is just how bad the LP is even from my Bortle 4, rural location. The gradient seen on the individual subs and the original stack of the Orion image from bottom to top is significant and some gradent is still apparant up through the images of Taurus and Auriga. Here's a single uncalibrated 2m sub exposure....

....and there was me thinking that I had dark, clear skies......

 

I definitely want to get a longer run at Orion, but with me setting up the SA rig each session I'm not sure that I'll be able to easily combine data from multiple sessions, hence I really need a good 1.5 hours to 2 hours (or more) on it from a single session, so fingers crossed for that.

 

Edited February 12, 2021 by geoflewis