not too sure how our weather is going to be that night - by the time i try to set up after work and my sons soccer training i would be lucky to scrape it in? how long and exposure would pick up enough info Dennis?
Iris is shown as mag 9.98 in Sky Tools, so I’ll probably be trying for sub frame exposures of around 3 mins, over a period of an hour or two to see if the motion of Iris will show against the background in that time.
Weather, equipment and stamina permitting, that is! LOL!
hmm thanks Dennis, I'm not sure if i'll be home but would be interesting to capture the pairing. My widefield imaging setup would fit them in no worries
Which way will the asteroid move and how long will it take to move?
The motion trace of Iris seems to be quite small, if I have things plotted correctly. Here is a screen capture from SkyTools showing the trace over 4 hours. FOV approx 20x15 arcmins.
Here is an image of the asteroid “7 Iris” passing close to the “Sombrero Galaxy”, (M104) as viewed from Brisbane on 5th May 2008, from 7:34pm to 10:10pm.
Images acquired with Vixen 4” F9 refractor and SBIG ST7E CCD camera. A total of 48 sub frames were stacked to show the motion trail. Sub frame exposures were 3 mins each.
The closest approach is tomorrow, Tuesday evening.
Here is a better copy, now that I have had the chance to get some sleep! Also, I noticed Iris appeared to be moving away from M104, yet The Sky seemed to show the close approach for tonight? Hmm, much check again.
I just checked with The Sky and toggled the views between 5th May and 6th May and it definitely shows the closer approach as 6th May. If you start around 7:00pm the altitude of M104 is around 50 degrees; it transits around 9:30pm so watch out for those meridian flips!
Thanks Mike – that kinda completes the circle, as that’s exactly where I first read about this event. A German amateur astronomer captured a nice wide field DSLR view earlier in the month and Dr Tony Philips published the photo on SpaceWeather.
I might even get a chance for another crack at this tonight if I can sneak out of a dinner engagement!
The clouds have decided whether I try for this tonight
Ouch Mike, that is not good news.
I’ve just set up the Mewlon 180 and spent an hour trying to orient my pitifully small 765x510 pixel CCD chip in the ST7 to include both M104 and Iris – it took some doing!
Also, the meagre sized TC211 guide chip (2.6mm x 2.6mm), with a whopping 192x164 pixels had problems finding a suitable guide star with the skewed orientation of the main chip. Added to that, the guide star corrections are bouncing around with a little too much of a large amplitude for my liking, but I daren’t touch anything now as it appears to be running itself whilst I type.
The night of May 6th promised an even closer encounter between the hyperactive minor planet 7 Iris and the slumbering giant galaxy, M104, also known as the Sombrero Galaxy.
Using my Takahashi Mewlon 180 telescope and SBIG ST7 CCD camera, I could just squeeze this enthralling cosmic spectacle onto the 765x510 pixel chip, by using a x0.8 reducer/flattener to bring the 180mm diameter telescope’s focal length down from 2160mm at F12 to 1728mm at F9.6.
I managed to capture 31 exposures between 7:26pm and 10:21pm AEST (GMT+10), showing the minor planet skimming the edge of the galaxy. The longer focal length “magnified” the movement of Iris between each 5 minute exposure, clearly showing the dynamic nature of this solar system interloper.
Oh the joys of imaging at longer focal lengths, using small chips, under light polluted skies! LOL!
