Thoughts on which imaging rigs to concentrate on

[Gina]

On checking the subs I seem to have 211 reasonable Ha subs of the Heart and Soul Nebulae from last night.  60s, gain 500, temperature -30°C.

[Gina]

Next I'll put the lens cap on and collect some darks and biases for -30°C as I haven't got these at this temperature.

[Gina]

Darks capturing proceeding   I'm hoping that if I can sort out PixInsight, I can post an image of the Heart and Soul in Ha in the DSO imaging forum.  It's about time I posted something again!

[cosmojaydee]

looking forward to see your results 

[Gina]

Moving files around to make room for the latest data.  I want to see if I can at least get something to post - I'll be gradually working backwards in capture time and seeing what data is any good.

[Gina]

ATM my working method is the move data from the HD on my astro laptop onto a 64GB SD card and then move the data from there to my Linux Mint desktop for processing with PI.  Transferring files over WiFi would take ages, one reason I'm thinking of using a 1 Gigabit HomePlug LAN - I'm hoping data transfer that way will be much quicker than WiFi.  Anyway, I'm currently moving files and when done I'll process in PI.

[Gina]

Looking at figures :-  The session last night produced 18GB of data which I'm now moving to SD card taking an estimated 26m then I will have to go back out and bring the card indoors and move the files onto the HD of the desktop.  Using Gigabit LAN I should be able to transfer about 120MB/s = 2GB/m so 18GB should take 9m to transfer across.  Or is getting a real 1 Gigabit data transfer with gigabit LAN being optimistic?

[Gina]

Another problem with the WiFi is that it has a habit of dropping off - I'm at the range limit even with a laptop.

[Gina]

19m left transferring files from laptop HD to SD card - it's a slow job with just USB2.

[ChrisLX200]

1 hour ago, Gina said:

Looking at figures :-  The session last night produced 18GB of data which I'm now moving to SD card taking an estimated 26m then I will have to go back out and bring the card indoors and move the files onto the HD of the desktop.  Using Gigabit LAN I should be able to transfer about 120MB/s = 2GB/m so 18GB should take 9m to transfer across.  Or is getting a real 1 Gigabit data transfer with gigabit LAN being optimistic?

Much depends on the cabling and how many connections/junctions/other sockets connected between, but the quoted throughput(s) for powerline connections are very optimistic indeed. Maybe they are achievable under ideal conditions but I never got got anywhere near the 500Mbit/sec quoted for mine (like about 20% of that...). It was that which prompted me to lay in a long ethernet cable from the Obs to the router in the house.

ChrisH

[Gina]

I see.  Thank you Chris

Since I shall be digging up the grass between house and observatory, I could lay CAT5E cable in MDPE water pipe in the ground under the weed membrane and gravel.  What bit rate do you think I could get out of that?  It would be about 15m long.

[Gina]

Used Blink in PI to look through my data and discarded duff frames.  I'm left with 199 Ha subs of the Heart and Soul and now running BPP in PI.

Following advice in the PI book, I looked at the bias and dark frames too.  The bias frames look fine but the darks appear to saturate.  Anyway, I'll see what BPP produces. 

Another puzzling thing was that PI objected to using a master flat created with the OIII filter for the Ha lights so I might have to produce flats for each filter if it looks as if the master flat hasn't been used.  Job for tomorrow or whenever the rain stops!

[hughgilhespie]

24 minutes ago, Gina said:

I see.  Thank you Chris

Since I shall be digging up the grass between house and observatory, I could lay CAT5E cable in MDPE water pipe in the ground under the weed membrane and gravel.  What bit rate do you think I could get out of that?  It would be about 15m long.

Hi Gina,

I suggest you install Cat 6 rather than Cat 5. It's about the same price and faster!

Regards, Hugh

[Gina]

Ah - is it...  I have a gert big reel of CAT5 but could buy CAT6 if it's faster and would make a difference.  Thanks Hugh

[hughgilhespie]

I'm not an expert but if you already have Cat 5, it PROBABLY won't make much difference over 15 meters or so. I think the speed measurements are based on a total length of 100 meters, of which 90 meters is the solid cored cable with 2 by 5 meter stranded, flexible bits at the ends.

There is also Cat 6A now - another chance to spend yet more money................

Regards, Hugh

[Gina]

Looks like it doesn't cost much eg. 30m waterproof outdoor cable

[hughgilhespie]

6 minutes ago, Gina said:

Ah - is it...  I have a gert big reel of CAT5 but could buy CAT6 if it's faster and would make a difference.  Thanks Hugh

Just a thought - if you have the crimper and a couple of sockets and plugs then why don't you make up a 'dummy' Cat 5 15 meter cable and try it. See what speed you get without all the grunt work of digging trenches, etc. It would only take an hour or so to make the cable..................

Regards, Hugh

[Gina]

Yes, I have crimper etc. so could indeed try it - thanks   Or just get a 20m outdoor grade cable as mine is only indoor rated.

Edited November 3, 2016 by Gina

[ChrisLX200]

Yes, you will get full speed out of your cable Cat5e or Cat6 over that short distance. It's better to use decent cable if you have it, one designed for use outdoors. Lay in a spare as well if you're going underground with it, the small extra cost may save a lot of hassle at some point in the future!  I laid two underground from Obs to pier, but just one to the house (although that one runs overground so easier to replace if needed).

ChrisH

These are what I used - much thicker cable than normal https://www.amazon.co.uk/gp/product/B00FSAL592/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

 

Edited November 3, 2016 by ChrisLX200

[Gina]

Decided to get the 20m version of yours Chris as I want to make sure it reaches - be a bit daft if a couple of feet short.

[Gina]

Here's the result from stacking 198 60s Ha subs using BPP in PixInsight.

[ringz]

Gina:

The reason that these small computers work in 32bit is because they then qualify for free windows 10.

Add more memory than 2Gb, bigger than 8" screen, if they have a screen, and work 64bit and then they come without an OS and you have to pay for the full version of windows 10. And before you think "I'll use Linux", that can have problems with the installing process.

[Gina]

Ah!  I see!  That makes the BoLv Z8700 Mini PC Beelink Z8700 MINI BOX / Win 10 64 bit OS pretty good value then at £159

[Horwig]

One thing to consider when running cat 5 in water pipe, as a friend found out some time ago, is that mice love it, so make sure the ends of the pipe are vertical, and sealed.

He just ran lots of lengths of cat 5, but the mice eventually eat through ALL of them

[Gina]

Yes, I've had rodent problems with cables in the past (mice and rats) but they don't seem to like eating MDPE.  I agree about the ends.