How to see the GRS?

I *REALLY* want to see the GRS. I'm sure i've looked at it before, but not sure I've ever really SEEN it. I think partly it's due to me having an 8" dob as opposed to a mak-newt or refractor that I have trouble spotting it. Over on the equipment board I just heard someone say, "Total beginners have no problems seeing the GRS in the MN56" and that pressed my buttons. I've been observing only a year and can get a good shot at Jupiter in the mornings from 45N 122W. My "starry night" program shows when it's in sight, but any other tips?

p.s. i do know that the image is reversed and flipped so i know to look in what appears to be the north eq band which is really the south eq band, but beyond that...i never seem to truly spot it....yet....


eqipment:
orion xt8 dob
tv 2.5x barlow
celestron ultima 30mm
celestron 6mm plossl
orion 9 & 25 mm plossl

The "Great Red Spot" isn't all that red any more. I haven't got out to observe it yet this fall but the last few years it has looked more like a very pale salmon color. You need a insrument with good contrast to see it well and I think that is one of the mak-newt's traits. I have seen it regularly in a 8" F6 newt (now a 7" F6.7) and my C8 but is can be a challenge sometimes because of less than optimal conditions.
Keep at it you'll eventually see it, it's just not going to jump out at you.



Robert W.

The GRS should be well within the capability of an 8-inch Newtonian with decent optics. And remember the following:

* The optics should be thermally stabilised
* Seeing must be good
* The planet should preferably be well above the horizon
* Use sufficient magnification. Possibly you will find 150 - 200x to be best
* Allow some time for your eyes to get used to the planets brightness
* The GRS should not be too far from the central meridian

The last point is important. More than two hours before or after meridian passage the GRS is difficult to see. For the first-time observer it may also be an advantage to know where the GRS is located. Scrutinise the southern edge of the southern equatorial belt. Good luck!

Hi Tom,

A good reference for GRS viewing is the Sky & Telescope website. Under Sky Observation, (Sky at a Glance) weekly schedule by day, they indicate the +/- 2 hour crossing times for the GRS. It's not observable that often during prime time.

Good Luck, Pete

Okay, I've absorbed all your tips. I've looked at Starry Night pro (macintosh) and picked the next best time to shoot for a GRS spotting.

Weather.com tells me it will be COLD partly cloudy monday at 6am here in portland, or (45* N), so I'll be taking my chances I guess....BUT...

At 4:00 PDT, Io's shadow begins to creep across Jupiter and does so until about 6:10, so there's something to look for as well.

Io itself transits from about 5:10 to about 7:20 (i guess that makes sense that they are both 2:10 in duration).

Now here's what is so good about that in my mind (besides never having bagged a shadow transit either. that should be cool too) At about 5:40 Io will be close, but just due north (jupiter's north) of the GRS. So there will be a nice little marker of where to look. There is also a seemingly high contrast but smaller storm in the NEB but in line the GRS. Both of these will be at meridian at about 6:30 (with +- 15 minutes being meridianish).

At the moment that Io emerges again out of transit, the GRS will be 3/4 of the way hmmmm...West? It appears from here to be moving left to right, which when looking up means east to west as opposed to west to east right?

So in my dob everything is flipped left to right and top to bottom, so all I need to do is maybe print the above schedule...and figure out ahead of time which way is which. Jupiter itself drifts from my perceived POV (earth rotating that is) from my FOV right to its left and is upside down. so i should expect Io's shadow to start it's transit from "my" (through the ep that is) right and move across through my (EP) left...as will Io, then the GRS (wich will appear to be in the "top" of the "top" EQ band (ie. the south of the SEB, only flipped). Are you with me? did I get that right?

The only non-perfect thing is that I am getting 12.5, 9 and 6mm UO Orthos Monday night, not monday morning, so I'm stuck with the just adequate 6 and 9mm plossls i have (plus my TV 2.5 barlow).

9 gives me 133...Or I could barlow my 30mm ultima to get 100x or my 25mm Sirius Plossl to get 120 with good eye relief...also, I have 23a red, 56 lt. green, 8 yellow and 38a blue filters...maybe the yellow?

any last minute suggestions?

Thanks for all the earlier ones by the way!

Tom.

I offer you a program called Planets 2.0.2 a java language downloadable file. Its neat. Shows right where to look for the GRS. Also Saturn. Shows positions of moons. All this as if looking in your EP. Bet you will like it. I refer to it all the time. I got it at www.tucows.com. Just type in the search engine the program name and download. Has alot of features so play around with it. Uses time lapse as well and you can know things years in advance. Best of all---its FREE.