groberts

I have just puchased a refurbished Lenovo Thinkpad laptop for dedicated astrophtography use. Outwardly it looks very good but I'm concerned about the USB ports. It was advertised as 2xUSB 2.0 and 2xUSB3.0 ports but visual inspection shows they're all black coloured i.e. no blue ones as per USB3.0 convention. I have looked at the Device Manager and there's something about USB 3.0 there but it's not clear to me if that confirms any of the ports are USB 3.0? Finally, however, two of the are ports are labelled with the little USB 3-wire symbol and the letters SS. Resorting to Google it seems to that the SS does denote these are in fact usb 3.0 ports and perhaps being an older computer are not colour coded i.e. blue. Can anybody please provide advice on these USB ports + in particular if I have, as advertised, 2xUSB3.0 and 2xUSB3.0 ports? Moreover, if these SS marked ports are USB 3.0 are they likely to cause any problems working with any modern USB 3.0 specced equipment e.g. astro cameras? Graham

Hmm, contary to my wishes it feels like I'm going down a technology rabbit hole here and in the KISS principle will maybe stick with staightforward (some of the time!) computer control. Many thanks anyhow. Graham

Many thanks, as is often the case this has sent me in a completely new (and unexpected) direction which, however, looks very interesting. I've had a brief look and have a few inital questions before delving deeper into things: Not clear why StellarMate has to run with Raspberry Pi + how, or is it stand alone? I'm not keen on moving away from my current software which is Windows7 + ASCOM/EQMOD + CdC + PHD2 + APT image capture - will StellarMate work with these or is it necessary to use EKOS + INDI etc.? The StellarMate website I'm looking at is all in US$ - is there a UK/European version + does it come from the USA? Graham

Tahnks for the comments - that's a pity about the non-ZWO support, which I suspected and is defintately something of a drawback. Will take a look at the Raspberry Pi idea but prefer something out the box. Graham

Toying with the idea of getting one of these rather than current setup of direct PC control for mount/guiding/image capture. However, I have a few questions + think I've read about isssues of compatililty: Is this only good for use with ZWO cameras? I use a ZWO ASI1600MM-Cool for imaging but with a Starlight Xpress Lodestar X2 for guiding - is this a problem? Can an auxillary USB hub be run from the Air Pro if addtional USB ports are needed? From experience what's the Wifi range? Anything else to think about + pros & cons? Thanks Graham

Bingo! Merci Patrick

Thanks Patrick - once in the correct directory do I then need to do anything else in the SetUp / Catalogue window to get things working? Graham

Thanks guys but I'm still struggling with this! You'll see from the screen grab below that SH2 is indeed indicated in theSetUp catalogue list but when I look at the directory there's nothing there. I therefore downloaded the given catalogue into the said directory (cat/sh2) and it still doesn't come up when I search for an SH2 object in CdC. I suspect I'm doing something wrong - any thoughts please? Graham

Thanks Andy - that link's very useful, is it somewhere on the wesbite too, can't see it?

Unfortunatly I had to miss the real time StarGaZine meeting last Sunday - where can I find the recorded version of this or any past meetings? Graham

Can anyone please direct me to a download source for the Sharpless Catalogue for use with Cartes du Ciel? Graham

OK maybe I'm getting things muddled - but am I therefore correct that putting that aside the aperture for say 100mm @ f2.0 is 50mm?

I want to input the field-of-view of a photography lens and DSLR camera into CdC to asssist with framing. This is quite simple with a telescope etc but when considering a camera lens set-up seems to become more complicated. For this pupose - is the correct aperture to use e.g for a 100mm lens with at f4 the the aperture is 25mm or 50mm at f2? Is therefore the correct number to use i.e. in this case either 25mm or 50mm depending on what f-stop you use, or is the size of the front lens element relevent? However, I presume that with say a DSLR the crop factor also needs to be included e.g. the CF for the Canon 700D is (I think) 1.61 so the previous apetures now become 54.33mm or 108.60mm (135 x CF / fstop). Is this correct or am I missing something? Graham

Any recommendations for a good optical bulb blower that will do a good job with astro cameras?

I'm embarressed to post this question but my brain's gone into meltdown - today's weather + covid-19 + passage of time! Can somebody please remind me of the workflow + settings in Deep Sky Stacker to create master files for a calibration library from individual sets of Flats / Bias / Dark FITS files i.e. independent of subs? I've done it before but let's just say it's been a while and I'm a bit rusty! Thanks, Graham

This is indeed most unfortunate. Perhaps if mid-week Stargazine is to continue, and I hope it is, maybe another night would be better - Thursday perhaps? Graham

For the record below is an answer I got from the PI Forum, which confirms my original suspicion that the problem was using FITs files. I had followed to the letter the excellent Light Vortex Tutorial which is shown working with FITs files but apparently things have changed with more recent versions of PI which will now only use .xisf files. I've therefore had to restack to produce new .xisf files which have just now worked fine in the aligment routine, which was where I originally crashed! Onwards and upwards to the next phase of my PixInsight initiation. Graham Answer from PI forum: The problem is as you suspected, the .fit format is too restricted for advanced processing techniques and Star Alignment does not handle drizzle integrated images in .fit format in the latest PI platform.This wasn't the case with earlier PI platforms and if you are following older tutorials they won't always point this out.In general the authors of PI don't consider .fit to be a suitable format for advanced processing techniques and the platform doesn't really support .fit except to import raw or export completed images.The error message is rather vague and unhelpful but that is the cause.You can import the raw data as .fit or pretty much any other image format but once you are into advanced processing you should only use .xisf until the completion of all the processing stages.Once the image has been successfully processed you can export as .fit or any of the other standard formats.There was a previous question on the same error earlier this year and that was the reason given by Juan to that questioner. Variant::ToDouble(): Invalid conversion from ByteVector type Hi, StarAlignment process shows this bug error: "Variant::ToDouble(): Invalid conversion from ByteVector type". It's important because I can't align the images. Curious thing is that it appears also alignment the picture with itself !!! The versi?n of Pixinsight is 1.8.8-2 Ripley (x64). Trying... pixinsight.com Sorry to be the bearer of unwanted news but the only way forward is to start again and stick to .xisf throughout the process.If possible, try to carry out the whole processing sequence in PI. It's not good practice to mix-and-match software during data processing as it makes it much more difficult to pin down where something went wrong in the sequence.

I've just downloaded these stacks to PI again which on the face of it went OK but gave the following warnings: **Warning: Variant::ToDouble(): Invalid conversion from ByteVector type and Warning Deprecated format: FITS This seems to clearly indicate there's something wrong with the said files but what is it? These were created in PI and then manually saved after registration - did I do something wrong in the saving process perhaps?

Thanks for the comments, at least it is 'normal' then - at this rate I'll need a computer the size of a house! These were stacked with PI but will take a look at BPP and see if that improves matters - when stretched the stacks themselves look OK. Graham

I have an as yet unresolved problem using Star Alignment on the thread below. But whilst looking at this it's drawn my attention to the file sizes generated using PI. In my case the LRGBHa 32 bit FITS stacks are each 250Mb - is this normal or a problem? Graham

Thanks for the guidance but I've tried the file conversion to .xisf and still get the same problem = something seems very wrong here?

Thanks for your kind words Wyvern. I've been very happy with the WO GT81 - though always thinking about something bigger, I'm put off by increased difficulties given our weather / limited imaging time and various other problems at my location. Hopefully one day I'll be able to establish an dedicated observatory and move on to something more ambitious. My images are all manual focus partly to keep it simple though I do own an electronic autofocuser - these things tend to sit in a cupboard for a couple of years and then possibly get used! I remain baffled as to what's happening here + why a second alignment is required? Did you use the given FITs file to align or convert to .xisf? The aligment settings are shown at the top of this thread in my original post. Graham

Hi Wyvern, haven't seen those videos so will take a look - thanks. It's taken a while to work up the courage / enthusiasm to tackle PI and despite it's supporters, I've got to say that this is probably the most user unfriendly software I've ever come across but will for the moment persevere! Ah yes hadn't noticed your gear is similar - I like to stick to the KISS principle and can't think how I ended up doing astrophtography. You'll find my story and images on my website given in the signature at the bottom. Processing to date has been almost entirely done with DSS and Photoshop. I've been back and looked at the Light Vortex workflow which shortly after the start + after downloading lights in the section Registering & Intergrating Lights says: We need to set one of these light frames as the reference image so that all the others are aligned in respect to it. From the small list box that says View at the top of StarAlignment, select File instead, then click the downward arrow button to the right of it. Select one of your calibrated, cosmetically corrected and weighting-optimised (and Debayered, if applicable) light frames. It is generally recommended you choose the image that has the highest optimised weighting (SSWEIGHT) as this will act as the best reference, especially if FWHM and Eccentricity were included in the optimised weighting calculation. As aforementioned in the previous section, do make sure this reference is free from satellite tracks and star blooming. So not sure why you're saying (a) this was not correct and (b) having done this we're asked to subseqently align the stacks? Thanks for the offer, as suggested + FYI I've attached just my L stack as an example - not sure if there's something wrong but the file sizes are enormous! Graham L Stack2d.fit

Wyvernp thanks for taking the time looking at this further. Such are the number of items required to deal with in PI that despite my very best efforts to stick to the excellent script (no pun intened) in Light Vortex, I might well have missed / misread one of the steps - as a long time user of DSS I also suspect I'm too condtioned by aspects of the protocol used therein. Your observation would certainly explain my confusion. Based on this I will endeavour to continue with what I have. Can I therfore use the FITS files I now have or do I need to either restack and save as .xisf files or open and ressave the FITS stacks as .xisf files? Given the above, I presume I therefore skip item 1.0 in this section and continue with 2.0 through to 4.0? Contents 1. Registering the Images with StarAlignment 2. Cropping the Black Edges with DynamicCrop 3. Subtracting Background Gradients with DynamicBackgroundExtraction 4. Matching the Images with LinearFit Graham

Thanks I appreciate the comments. I did align all the waveglengths using a single 'best' luminance sub fo LRGB & Ha and was therefore surprised to have to do this a second time but that's what the Light Vortex Tutorial seems to say or have I misunderstood? https://www.lightvortexastronomy.com/tutorial-preparing-monochrome-images-for-colour-combination-and-further-post-processing.html#Section1 I have tried again + unticking the 'generate drizzle data' but with the same result. David I take your point but I'm doing every filter to arrive at a final image (a) repeating each stage for each filter reinforces the learning, though it does take longer, and (b) I would like to end up with a final colour image to compare with my original DSS + Photoshop image. Just to clarify the other point - is there a preferred file format I should have save the stacked images in or would either FITS, TIFF or xisf be OK at this stage? Graham