From: Jim Chung <jim_chung@sunshine.net>

Date: October 18, 2017 5:12:22 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Re: Rare dual solar and lunar ISS transit

It's quite visible even in the daytime sky  - if the Moon is low then an IR pass filter might be very helpful.

Good luck.  We need more dual transit images to pique interest from others!

Jim

Quoting "ursamajor_1@mac.com [Astro_IIDC]" <Astro_IIDC@yahoogroups.com>:

Hi Jim,

 i was looking at your ISS-Moon transit image again and wondering how easy (or not) it was to pick up in the ISS in daylight?   I have a ISS-Moon transit near me, thats predicted for this Sat. around 5:45pm so it will be in daylight with Sun also low in SW.  This will be a very thin crescent Moon however.   So not sure its worth chasing.  Thinking I could maybe use my IR pass filter to darken the blue sky but maybe cuts too much white light.   Thoughts?      and thanks.    Ron

---In Astro_IIDC@yahoogroups.com, <jim_chung@...> wrote :

Hey everyone!

Not sure how rare this event is, obviously both the Sun and the Moon have to be in the day sky together so that does limit how often this phenomenon can occur, and rare in that it occurred on a weekend and on a nice day as well!!!

Since I've taken a few solar and lunar ISS transits in the past, I'm not so inclined to keep doing it but this dual transit caught my attention and motivated me to try it again.

So I had to drive about 5 km in the city to get on the centerline and as usual I was in a hurry and wanted to take the bare minimum of gear since that's less to setup, cleanup and lose.  So I figured I'd take just one scope, my dual stack 40mm Coronado solar scope, and image the Moon in Ha as well.

Caught the Solar transit at 8:20 and slewed to the Moon.   Could not see a damn thing.  Of course not.  Cuz the bandpass of a solar scope is way tighter than narrowband Ha filters and there's the additional blocking filters and IR blocking filters in the diagonal too.  I removed both etalons but instead of a normal refractor, the Coronado has the lens objective screwed to the tilting mechanism of the first etalon.  Plus the draw tube could not extend far enough to get the camera or eyepiece into focus without a diagonal in the optical train.

Good thing I had over an hour to try and salvage this opportunity,  I ransacked the car to see what materials I could use.  Found my 25 year old first aid kit that has followed me from car to car to car and while the insulating foam rubber has decayed to powder and all the meds had followed suit, the sealed wound closure strips were still very sticky and could serve as ersatz duct tape!!

So I wrapped several layer of strips around the lens objective so that it could be jammed into the front of the scope in a position several centimeters ahead of its normal position to bring the focus point forward and taped a B&W red filter in front to lower the light intensity and sharpen the image of the low setting Moon.  By placing the camera at the very tip of the focusing draw tube, I just managed to achieve focus.  I had 20 minutes to spare, so I did some public outreach and solicited some potential RASC members from curious people in the parking lot.

Here's the  Coronado scope rigged for visible light:

https://www.dropbox.com/s/lxgf5boy986fjnw/P1000693.JPG?dl=0 https://www.dropbox.com/s/lxgf5boy986fjnw/P1000693.JPG?dl=0

And what we've all been waiting for, the first dual ISS transit taken with PGR Grasshopper ccd and ASTRO IIDC (and maybe the first dual transit ever imaged):

https://www.dropbox.com/s/x1vmf798hjb21ia/ISSDualTransit.jpg?dl=0 https://www.dropbox.com/s/x1vmf798hjb21ia/ISSDualTransit.jpg?dl=0