Requiem for Relativity

You do not want to use a filter. If the target is at or near the detection limit of the scope adding a filter is just going to make it disappear altogether.

Are these images being calibrated? The last one posted appeared to have a lot of vignetting so it appears it wasn't flat field corrected at least. Without proper calibration the images are going to have a lot of 'noise' making detection of objects unreliable.

Cheers

Bill

Hi Bill, won't a red filter lighten the reds and dim the blues? Obviously it will mean upping the exposure to compensate for the filter but we're just after movement over two plates. I think it will just come down to the fact that the Bradford isn't big enough to do the job.

(edited)
03 21 36.36 +06 18 17.5 Sedna
01 38 19.71 -04 52 36.5 Eris

So these two are at perigee about 180 degrees from Barb. They are both about Pluto mass, and there must be more of them, which are way out in the boonies at the present time.

Hi Bob,
No, filters will cut light to the CCD. A Red filter will allow red light through and block the other wavelengths so a red object will appear brighter than a blue object but you have still cut the amount of light getting to the CCD. Whenever dealing with anything close to your detection limit, you do not want to use anything that will limit the amount of light your CCD will receive.

Cheers

Bill

Bob,

Given the poor racking in NEM10 and 12, will Bradford allow you to select guiding? If not then you might be better off using shorter integrations and then stack the results.

Cheers

Bill

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Stoat</i>
<br />Sedna (the inuit goddess of war, I think) goes from 76 to 990 AU.

UB313 is now titled Eris (A Greek goddess) I don't know its eccentricity but the drawing up on the web site for it suggests a large eccentricity as well.

I don't know about you but I'm always wary when the explanation of something is a rogue passing sun. I take that as meaning, "we haven't a clue why."

Data on the two objects can be got from here. ssd.jpl.nasa.gov/horizons.cgi

I got image 12 back from the Bradford, should I put it up? As it looks like it will miss the revised position of old Barb. Maybe new jobs put up with a red filter to bring out the dwarf?


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Thanks for the info & link. I'm also wary of the rogue sun idea, especially because elsewhere on this site I've theorized that even what little interstellar red- & blueshift there seems to be, might be mostly non-Doppler.

If convenient, please do put the image up. Somebody else might find something before I do. The Bradford photos have improved dramatically and I have high hopes for them. It's OK if the coordinates are a little off because the still-uncertain Barbarossa-Frey orbit introduces several arcminutes uncertainty.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Bill_Smith</i>
<br />You do not want to use a filter. If the target is at or near the detection limit of the scope adding a filter is just going to make it disappear altogether.

Are these images being calibrated? The last one posted appeared to have a lot of vignetting so it appears it wasn't flat field corrected at least. Without proper calibration the images are going to have a lot of 'noise' making detection of objects unreliable.

Cheers

Bill
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Dear Bill,

Thanks for your expert input. I mostly look at Red sky survey plates because these are the commonest, and have the best resolution and sensitivity.

Stars are rather sparse in this part of the sky. It hasn't been too laborious to rule them out by comparison with plate images.

- Joseph C. Keller