VectorQuantity

This is the two part [7704] flattener/reducer which comes with spacing rings for a Borg 101ED (amongst others). I am or course missing these spacers. This is for use with an EOS and wondered if anyone can tell me what thickness they are since the only Borg info I can find usefully refers to them as being 'thick' and 'thin'.

Hello Stuart, Having selected your usable sub-frames and calibrated and corrected, pick one of them. Align/register all other subs irrespective of the filter type to this sub-frame. You could of course align individually for each filter having picked a suitable sub-frame as reference for each filter from that filter set, then you'd have to align the masters. I believe some people (not me) if using the first method also run a subsequent step to align/register the LRGB masters prior to combination, not sure why. n.b. make sure you correct the subframes i.e. get rid of artefacts prior to alignment/registration to ensure the software you are using does not detect hot pixels as stars.

There used to be fairly inexpensive software for this from optictracker.com. I considered purchasing it a couple of years ago but never did. It seems it's now no longer sold. https://www.youtube.com/user/optictracker/featured

If it's only 1W then that's great, your peltier should have no problems.

Hi Danny, PSU. Appears to be OK and it's a good price so not the end of the world if it turns out not to do the job. You should indeed be able to use it to adjust the peltier heat pump to an optimal value. here's a link to a more detaied description. https://www.aliexpress.com/item/4000197872662.html

re: 1. Yes you are correct, it's the applied peltier power. re: 2. You would expect the o/p voltage to stay at its set point unless it's in current limit, i.e. not to change until you reach a current draw of 4A. Do you have a part number/link to the psu? Do you know how much power your camera consumes?

Hi Danny, 1. Apologies it's a bit ambiguous are you able to re-phrase the question? 2. Is it a buck convertor (step down) or a boost convertor (step-up)? It could theoretically be both but that's unlikely. The majority of output protected convertors will current limit at which point it appears as a constant current. You shouldn't be running at the current limit point, this exists to prevent destruction of the PSU and the attached load. 3. The peltier isn't a cooling device, it's an inefficient heat pump, in addition to having to get rid of the pumped heat you also need to get rid of the applied power that provides the heat pump action, if you don't then the temperature delta falls eventually to zero then goes positive and you have a heater. The most important thing is getting rid of the heat which is hard to do with a non-blown heatsink. Your example of the cpu running at 70 degress unfortunately doesn't tell you much as the cpu is additionally connected to a significant PCB heatsink not just the added heatsink. The degC/W rating assumes perfect heat transfer into the heatsink, you'll also need to factor in the degC/W of the heatsink transfer material probably silicone pad or thermal oxide both of which have poor thermal transfer. The metal oxide is superior but likely to add 0.4 degC/W, the silicone thermally filled pads maybe 4 to 8 degC/W. As far as the fan goes you're interested in the total volume of air it moves rated in either cubic metres per minute or per hour. Your fridge example is a thermal mass that's not being heated so easier to cool, and it's probably been on for many hours to get down to temperature, your camera heats itself so a comparison isn't that valid. I'd start by having a peltier that doesn't have to be driven hard then you don't have added heat to get rid of, thermal oxide to the heatsink then a heatsink shape that ducts onto the fan and then a high flow/volume fan. The other option is a non peltier and purely fan blown one, that may keep you close to ambient without all the hassle.

It's 5.2 x 5.2 micron (SSAG #52064)

You should be able to. Assume it's along the lines of - Guide Camera to computer USB to PHD2, PHD2 to computer USB to st4 adapter, st4 to mount. But if your guide cam has an ST4 port then Guidecam (On-camera selection in PHD2) to mount ST4 would be simpler.

From a second camera for comparison. Kaf16200 139off 600seconds at minus 20. same effect is visible. Rescaled to 50%.

Yep.

This is a max stack of 179off 600 second darks at minus 20. KAF8300. It's covered with the things. Seems to have an average distibution across the frame. Also the track angles are random, I assume this means it's a not a point source.

The second doc (D.Groom) mentions something interesting in that there's an exception to gamma/X-ray generating these 'worms' and that's a beta particle orginating from Potassium decay in BK7 glass i.e. Crown glass which of course can be used in APO's even if some lenses are FPL51/53. I have however seen this effect when imaging with numerous scopes which may point to it being an external source and not 'scope glass' related.

Thanks that's a useful doc. This document characterises this as most likely a 'worm' but without giving much information about how it arises, but it references 'D. Groom. Cosmic rays and other nonsense in astronomical ccd imagers.' which I've found at https://www.astronomy.ohio-state.edu/MDM/OSMOS/CCD_CosmicRays_groom.pdf. This one's more detailed and if I'm reading it correctly implies it's the result of a gamma or x-ray hit.

For years I've noticed artefacts similar to that in the attached image, a 60 second 300x300ish crop from a single CCD frame. Since these are removed by stacking it's not been an issue but I've always wondered what they are. I have some ideas but thought I'd put this as an open question.