so a while back i purchased a camera and filter from an IISer, the filter wheel was loaded with LRGBHa and SII filters but for whatever reason one of the NB filters was not there, the guy was god about it and returned some money for it but now i am in the position where i either have an Ha or SII filter in my filter wheel and i want to buy the other one. i think it is the Ha, but to be honest i have no good reason for thinking that, other than Ha is generally the most used filter and it was in the slot after the visual filters were in, in the standard order. but before i drop some decent money on a filter i already potentially have, is there an easy way to determine which one it is? preferably i would like to do this remotely and not have to drive to the observatory and open up the FW. i am assuming there are some targets out there that have very distinct NB regions.
For doing this remotely just shoot something like Eta Carina, which has lots of Ha but much less Sii. If you see it well defined its the Ha filter, if its spotty with gaps its Sii. Works on the Lagoon as well.
i just dont know if the distinction between the two is something i can trust myself to pick up in a couple of subs and without having both filters to compare side by side. maybe a planetary neb would be more distinct. Helix would be pretty good but it is not up at this time of the year
Totally agree with the two suggestions, Eta carina will be a dead give away, looks dense and bold in Ha but far more tenuous and patchy in SII - easy! :-)
Take a 5min sub, it should be obvious to us all from that
it appears that my observatory is under permanent cloud cover ... i couldn't take the image. i have a friend with some land out in Bathurst who offered me some space for the observatory and i am seriously considering taking him up on the offer, should get much better weather conditions and seeing ...
so this is a 60 second image of Eta carinae that i took last night. i have my thoughts on what it is but i want to see if that is consistent with other people. no stretching was done to the image, i saved as it appeared in FITS liberator which defaulted the white slider up the curve.
I would be leaning toward SII too. it shows stars more prominent than Ha. however I probably would have gone for a target with next to no Sii to be sure to be sure. eg running chicken neb near the boks.
should i do a Red and NB image side by side to compare, would that make it easier to distinguish? i really don't want to buy the same filter again so i want to be pretty damn sure
should i do a Red and NB image side by side to compare, would that make it easier to distinguish? i really don't want to buy the same filter again so i want to be pretty damn sure
In the end there is only going to be 2 different ways to know for sure. The first one is to go down there and read what is on the side of the filter. The second if the guy who sold it to you had a full set, which seems likely. Why not contact him and see which one he still has. If he only bought 2 then it would most likely be HA, because I cant think of a reason to get SII and OIII.
In the end there is only going to be 2 different ways to know for sure. The first one is to go down there and read what is on the side of the filter. The second if the guy who sold it to you had a full set, which seems likely. Why not contact him and see which one he still has. If he only bought 2 then it would most likely be HA, because I cant think of a reason to get SII and OIII.
Believe me I have contacted him and he doesn't know, he bought both ha and SII and both were supposed to be in the fw but only 1 was. Also the filters are unmounted, just glass edges like this https://www.optcorp.com/ba-fsiin-rd5...unmounted.html
So I will need to deduce it. I also took an image of m83 last night thinking that ha regions would show up clearly and almost no detail was showing which makes me agree that it is an SII filter, I will post that pic tonight along with an image of the running chicken neb
