Electric filter wheels. Not convinced.

[ollypenrice]

I put that information in the file name as a matter of course. I don't put the object name in because one object goes in one folder, so it might be L900-25 B1 (Luminance, 900 seconds, -25C, Bin1.) If I come back for more on another night I insert N2 as well. (Night two.) This is because my stacking software, AstroArt 5, won't accept two files with the same name. If I do a second run and start the counter at 1 again I would get the same name on the second night without the N1/N2/N3 in the file name.

I suppose you can't create filenames with a DSLR and no laptop? Nightmare!

Olly

[ian_bird]

Hi Per

You said "The SX one has failed to initialize upon power on a few times but that's easily fixed by pulling the cable and plugging it in again (which I can do with software)"

Could you tell me how you do that? I have to physically unplug mine for it to initialize.

Thanks

Ian

[opticalpath]

Back to the original topic.....

If you use a manual wheel do you have to write down what filter was used for a particular exposure number? How do you keep track?

If you use Maxim (other software is available) to control the imaging camera and an electronic filter wheel, it does it all for you. You just tell it once what filter is in each slot and after that every saved image records the filter information (as well as all the other exposure details) in the FITS file header, so the information is collected automatically and stays with the file forever. Additionally, you can specify a filename suffix for each filter to automatically include, for example, 'red' or 'Ha' as part of the filename for easy identification later.

For me, that is one very worthwhile benefit of having a PC-controlled EFW, compared to a manual one. The other one is the ability to automate a sequence of exposures: R,G,B,R,G,B,R ....etc so I will always get a balanced set of RGB, even if the session has to be abandoned early; that would be impossibly laborious manually.

Adrian

[Zakalwe]

If you use Maxim (other software is available) to control the imaging camera and an electronic filter wheel, it does it all for you. You just tell it once what filter is in each slot and after that every saved image records the filter information (as well as all the other exposure details) in the FITS file header, so the information is collected automatically and stays with the file forever. Additionally, you can specify a filename suffix for each filter to automatically include, for example, 'red' or 'Ha' as part of the filename for easy identification later.

Do you have to re-focus each time the filter changes?

[opticalpath]

I remember the old acoustic couplers, teleprinters and teletypes as the Americans called them, Ian. Been there done that but not sure T shirts had been invented My first programing was done using a teleprinter connected via the ol' telephone network to a room full of computer in a university. That was back in the 1960s

Ah yes, brings it all back ..... that friendly burbling tone before the line settled down to a steady 600 bps, the familiar chatter of the nodding golfball teletype .... interrupted only by an anguished cry as the paper-tape reader shreds someone's latest creation.

Adrian

[opticalpath]

Do you have to re-focus each time the filter changes?

Fair question. With my Mak-Newt, I don't and I admit that does make a sequence: RGBRGBR ... etc. very straightforward. If I had to re-focus between filters, though, I could also program in focus offset adjustments for each filter via the PC-controlled focuser (but don't mention that to Olly or it 'll set him off about those too ) In practice, though, if I had to make focus changes I would go back to taking separate sequences with each filter.

Adrian

[Zakalwe]

Thanks Adrian,

What filters are you using? I'm about to take my first steps in RGB imaging....

[Sp@ce_d]

Most folk.. ( myself included) seem to find the Baaders pretty much parfocal

[Zakalwe]

Most folk.. ( myself included) seem to find the Baaders pretty much parfocal

Luckily, they're the ones that I bought!

[opticalpath]

Thanks Adrian,

What filters are you using? I'm about to take my first steps in RGB imaging....

I have a set of Astronomik LRGB and narrow-band filters. There are other brands of course that are popular and well regarded, such as Astrodon and Baader, but I don't have personal experience of using those.

Good luck!

Adrian

[IanL]

I remember the old acoustic couplers, teleprinters and teletypes as the Americans called them, Ian. Been there done that but not sure T shirts had been invented My first programing was done using a teleprinter connected via the ol' telephone network to a room full of computer in a university. That was back in the 1960s

You win! (Though I was taught the history of computing at Uni by a prof that claimed his first job after he left uni was programming LEO). My first brush programming was done by writing stuff on coding sheets and posting it off to the local technical college so they could send a 'syntax error' printout back a week later. Taught me a thing or two about discipline. Wrote a 3D graphing program for a teletype next, then the school got something called a 'microcomputer'; a whole computer to ourselves (all 800 kids!)

[ollypenrice]

I've found the Baaders entirely parfocal down to F3.9. A caveat arises with regard to the quality of your optics. If they are not perfectly corrected then the focal point will change with the spectrum. If this is the case then you should ideally refocus and use a sophisticated stacking routine such as that of Pixinsight or Registar which will adjust the geometry of the image to allow for the small change in focal length associated with changes of focus. The parfocality I mention at F3.9 was in our Tak FSQ85 which has phenomenal colour correction.

In reality we use Baaders on Yves' ODK and on all our in-house scopes and I've never seen any need for refocus in any of them. This is great!

The darned FW is working perfectly in a new PC but it only has three USBs so the old one is guiding. USB hub, you say? Don't get me started!!!!

Olly

[Sp@ce_d]

Ah.. hubs.... now only today.. err yesterday.. I was singing the praises of the HitecAstro Mount hub pro. Great bit of kit.. specially for remote.. all that luvly computer controlled switching on & off.. adjusting the dew heaters, focus poweroutlets .. you'd love it... nice and techy. Oh and did I say it has USB ports..

[ianaiken]

I must admit I use an EFW2 without any issues at all (once I initially adjusted the mechanism). I control it using Sequence Generator Pro allowing me to automate significantly. OK it is connected via a USB Hub to a desktop PC in the OBS so it gets ample power. The hubs (yes plural) are actually mounted on the tandem bar on the mount - I have 7 USB devices plugged in. This means less cables to route down the mount.

[DaveS]

I got landed with Vista last time because XP had just disappeared and I don't want to get bitten twice by getting a Win8 machine. I suppose I'll be able to get a new WIn7 somehow?

.

Olly

Olly,if you move quickly Dell business are having a sale of win 7 vostro laptops. I'm ordering one through the school to replace this clapped-out lappy I'm typing on now.

[Sp@ce_d]

Olly,if you move quickly Dell business are having a sale of win 7 vostro laptops. I'm ordering one through the school to replace this clapped-out lappy I'm typing on now.

One of my colleagues at work had to replace his last week..he didn't want Win8 but it now seems some places are now charging more for a Win7 than a Win8 though..

[DaveS]

Yeah, that's what I found, but Dell are doing an offer, so it's not too much of a hit.

[Jessun]

I suppose I'll be able to get a new WIn7 somehow?

Not on a pink laptop.

/Jesper

[Zakalwe]

Olly,

You can buy the OEM version of Win 7 for £70

http://www.scan.co.uk/products/microsoft-windows-7-home-premium-32-bit-sp1-operating-system-single-oem

When installing it just select to format the hard disk (back your data up first, natch). Job jobbed.

[ollypenrice]

Thanks. I have a pal who will guide me through all this... Poor fellow.

Olly

[DaveS]

Good to know, thanks.

*Feels stupid* Bought kit from Scan before (Two video workstations and a graphics card upgrade)

[Paul81]

Having had to use USB in military applications, my experience is that the biggest reliability issue with USB is two things, firstly the dreadful connector, and secondly the second rate software.

The connector is fine for printers, mice and keyboards - things that stay in the warm in nice desktop environments. Now astro use in nothing compared to military, but the connectors hate damp and the metal work is prone to issues with regards to thermal changes. Although military connectors would add a huge cost to the gear, I am surprised more manufacturers do not do simple things like have connectors with screws either side (like in the photo posted by someone in a previous post. Simple but keeps things plugged in.

In terms of the software, I always have a major gripe that most manufacturers rush their software out rather than ensure it does what it says on the tin, but then again if they used robust engineering practices then the cost would increase...

However, I am surprised I do not see any real mention of the imagers on here creating embedded Windows builds for their imaging computers. Most of the software out there seems to be mainly targeted at Windows (which is a shame..), but I believe MS still have the Windows Embedded product, which is a componentised Windows 7. This would allow you to create a dedicated build of the OS just to run the astro imaging software (would work best with a single program that performs all the functions). The advantage is there is less rubbish to go wrong and kill the session, and also you can have the OS image on a read only partition, thus Windows cannot mess with its registry etc so it becomes much more robust and boots as reliably as Windows can. Naturally, you would need a second writeable partition or external disk for your data. Creating these things is a bit of work, but hey there are enough cloudy nights...

I am a visual observer (although I design computer systems for the military I like my astro nice and simple), I have looked into video type astronomy.I was quite interested in using an SX lodestar. I have seen SX docs with details of their USB protocol so my thought was to create some software to capture, integrate and display live(ish) images. The plan was to use Linux as the OS as you can make some nice small and ultra reliable boot images that can just be loaded as and when and I am fairly confident it would all just work... <cough> of course I'd have replaced those dreadful USB connectors...

[Gina]

Yes, it's a great pity IMO that most astro software is Windows only. I've been using Linux for many years and was virtually forced to use Windows for astro use. OK I know there are Linux apps but these simply do not match up to the Windows ones. I really miss the reliability of Linux - computers running for years without a single hitch let alone crash. I run a netbook with XP SP3 for capture and control and a core-5 desktop running Win 7 Pro 64 bit for processing. I quite like Win 7 it's a lot more reliable than XP though still not up to Linux standards and MS have taken some user feartures from the Linux/Unix camp, which is nice.

[jnc71106]

i used to use a manual wheel and was very happy with it, my hand was forced slightly when i bought a mono planetary cam and the thought of sitting there having to cycle through the filters every 60 secs or so was not very appealing. I picked up one of the original Atik electric wheels pretty cheap and i absolutely love it, setting Artemis to capture L,R,G,B,L,R,G,B like Gina means i will always go home with an image even if the night is cut short

Like Olly the colour correction on my scope is as near to perfect as can be so refocusing is not something i have to do.

As for USB disconnects, little stick on cable clips stop that happening for me if a cable is snagged it will pull on the clip before it pulls the USB out

EFW = One Happy Chappie

[ollypenrice]

Paul 81, you are going to love the connectors on the Lodestar. If they are bad in general this camera makes an art form of badness!. They use a daft mini usb which hasn't a cat in hell's chance out of doors and the two cables are so close together than many manufacturers' cables are to thick to go in side by side so one beds the other over. Telescope Service do a costly widget to help sort out this poor design.

Olly