Scorpius

On 25/01/2021 at 10:17, nephilim said:

Also can anyone point me in the right direction for the correct size heater for the Samyang?

Measured the outside diameter of removable dew shield on my Samyang 135/f2 & it's 93 mm. So the minimum length dew strap you'd need (not counting any unheated Velcro) to completely encircle the dew shield is 29.2 cm (2π · r ÷ 10)

On 25/01/2021 at 09:08, JohnHWhite said:

Give yourself plenty of room, and gather together a good portion of patience, as well as any tools that are required for assembly before you start.

Plenty of room, a lot of patience and tools - got it & thanks for the tip. Btw - just noticed in your post where you quoted me there's a link to a UK sheet materials wholesaler that was not included in my original post which is very strange 🤔 ( all sheetmaterials I bought here  https://sheetmaterialswholesale.co.uk/

File cabinets, lights & blackout curtains...

33 minutes ago, Physopto said:

A good plan from what you have said.

But be careful when working around the astro gear when it is in place. Not trying to teach granny to suck eggs but.....

I know from bitter experience about how easy it is to stumble or slip when distracted. I have damaged several items in our house trying to speed up renovations, when I thought I could get an item in without hitting something. Worst was a kitchen cupboard door. I managed to scratch right across its front. Of course it was not replaceable, as not manufactured any more. So 9 new doors and several drawer fronts to purchase!!

I also ripped my rotator cuff in my right arm trying to do a job alone when I could have waited for my wife to help when back from work. Still not right 8 years on. 😠

 

I agree with not working around the gear and that’s why I haven’t moved anything in and continue to resist the urge to squeeze in some astro sessions when the skies are clear. When it comes time to finish the obsy walls, I’ll probably store what I can in the pod and then put the rest back in the nearby gazebo where it’s currently kept in plastic cases.

As far as body aches go you are preaching to the choir! LOL My wife will always help if I ask but I rarely do since she’s developed some mobility issues in recent years that prevent her from doing much lifting/climbing, etc. What you see in the photos was done almost entirely by yours truly with some limited assistance from family members along the way. I’ve worked construction in some capacity for 40+ yrs. and have so far learned to live with the aches and pains of getting older.

21 hours ago, Physopto said:

Looking really good. As far as the obsy walls go I would internally insulate and board it out before you put in your gear. It will make it much less prone to temperature swings between day and night, but also much more secure.

Nice!🙂

Thank you very much! I do plan to insulate and panel the main obsy but it will probably have to wait until spring. It's been very wet this winter and the work area outside is quite muddy from all the foot traffic and that mud gets tracked back inside every time I go out to rip a piece of paneling, etc. Waiting will also allow time for my wallet to recover which is no small issue at this point and I'll finally get to use the structure and all the astro gear I've purchased for the intended purpose. Although it may not be 100% complete, it's easily close enough to use for now with the final push toward completion planned for warmer/drier weather that's only a few months away. 😃

In a side-by-side configuration, any tips for aligning the finder scope with a Canon 60D and also, while doing a Celestron handset star align - how do you perform the second step (center star in eye piece and press align) when the camera itself has no eyepiece? The kit is an Advanced VX mount, a Canon 60D with Samyang 135mm/F2, an Orion 60mm finder/guide scope Orion 60mm Multi-Use Guide Scope with Helical Focuser | Orion Telescopes and an ADM 11-inch side by side bar VSBS- V Series Side-By-Side System. 11" Connecting Bar - ADM Accessories  with camera mount VDUP-CM- V Series Universal Dovetail Camera Mount. - ADM Accessories and 7-inch dovetail bar for the scope VDUP7- V Series Universal Dovetail Bar. 7" Long - ADM Accessories I also have an assortment of riser blocks to raise the scope to the same elevation as the camera. This will be my first attempt at DSLR AP as well as a side-by-side setup so all advice will be greatly appreciated.

2 coats flat colonial white latex on walls, 2 coats non-skid gray porch paint on floor and 3 coats polyurethane on desktop. Just need to hang blackout curtains and install rope lights and then control pod is finally done!!!

A few progress pics of control room or “control pod” as I call it since the space is quite small. By small, I mean about 5 ft. 6” (167 cm) wide x 5 ft. (152 cm) deep with a sloped ceiling 6 ft. (182 cm) at front opening and about 54” (137 cm) at rear wall. There will be two, 3-drawer file cabinets under desk which are on order from Staples -  Staples 3-Drawer Vertical File Cabinet, Mobile/Pedestal, Letter, Putty, 20"D (24871D) at Staples With cabinets in place there will be just enough room for an office chair in between however, they have built-in casters so they may be rolled out if a visitor - such as the wife - stops by to check out the imaging process or to find out where all the money has gone 🤔

So, without further ado here are the photos:

Control pod now wired and fully insulated. 2” conduit routed under floor connecting control pod with underfloor compartment adjacent to pier.

Paneling is 3/8” pre-primed, simulated wood grain OSB.

Desktop is manufactured 64” wide, 25” deep, 1 ½” thick butcher block sanded and sealed on all sides with 3 coats quick dry, satin finish polyurethane.

So, now the only items that remain on the list before pod is complete are:

Caulk joints and install molding.

Apply latex topcoat to paneling which will be off-white, or colonial white to be exact.

Install 1 string of white and 1 string of red LED rope lights powered by outlet controlled by duplex switch mounted near top of left-hand pod wall in photo.

Hang thermal blackout curtains to hold in heat and limit amount of light escaping from pod to main observatory.

Next big decision is whether to insulate and panel main observatory walls or just leave them as is so I can start using the obsy. I do not want to bring in my astronomy gear and set everything up until the major work (and mess) is complete and most tools and building materials have been moved out. What would you do?

5 hours ago, nephilim said:

That's a bit expensive for a Bahtinov Mask does the fact it'll have WO on the box add 40% to its cost 😁. I think I'll just get one for  £10 as there are quite a few people making these on a 3D printer. 

I believe the price has more to do with the type of material it's made from than what it says on the box. Apparently, it's produced from optical grade acrylic which supposedly has 92% light transmission producing 3x brighter diffraction spikes. However, the 3D printed ones are probably almost as good at only 1/3 the cost 😉

On 23/12/2020 at 16:04, Alien 13 said:

Nice pattern and the focus is almost spot on, must try one.

Alan

Almost spot on? So additional fine tuning is still required? Just ordered one from High Point Scientific here in the US William Optics Diffraction Spikes Bahtinov Mask for 75mm-110mm Dew Shields - BM-DS-GR45 (highpointscientific.com)

5 minutes ago, Pryce said:

Followup.  Would it in that case be OK to use a 12v plug that branches out to two sockets or would that cause issues?

As long as you don't exceed the rating in amps of the single 12 volt socket, you could have as many branches as you like but you do need to know the amperage rating of the single socket and also the load of everything you'll have connected to be sure. If the 12 volt devices are labeled in watts instead of amps here's an online converter you can use: Watts to Amps (A) conversion calculator (rapidtables.com). Cheaper 12 volt sockets may only be rated for 5 amps which means you could only safely pull 60 watts (5 amps) continuous. On the other hand, if it's a heavy duty 12 volt, 30 amp socket, you could safely pull 360 watts (30 amps) continuous through multiple branches. If the devices are labeled in milliamps (mA) divide by 1000 to find the load in amps.

Some things like the mount and dew heaters are 12 volt but other stuff like laptops and powered USB hubs will be 110 volt (in the US) or 230 in your case. You may want to get a mains power supply for the mount. I've heard this Celestron power supply will run an EQ6 but you would need to confirm that's true Amazon.com : Celestron 18778 AC Adapter (Black) : Telescope Accessories : Camera & Photo Then a converter like this could be used for accessories like dew heaters: Amazon.com: AstroAI AC to DC Converter, 10A/110Vto12V DC/120W/7.78FT, Car Cigarette Lighter Socket AC/DC Power Supply Adapter Transformer for Inflator, Car Refrigerator, and Other Car Devices: Automotive This way you could run everything off a multiplug outlet connected to a suitable extension cord connected to a nearby mains plug.

59 minutes ago, Pryce said:

If thats natural, how do people even image at all during winter without main? 

Just now completing the electrical system in my off-the-grid ROR observatory. The main components are a 200 Ah Gel battery powered by a 600 watt solar array connected to a 3000 watt pure sine wave inverter. When I was setting up on a tripod I used one of those power pack type batteries and it never lasted through the night.  Most folks suggest something in the neighborhood of a 100 Ah deep cell battery which will provide extra power for things like dew heaters, laptops, etc. Here's the 100 Ah version of my Renogy battery Amazon.com: Renogy Deep Cycle Hybrid Gel 12 Volt 100Ah Battery: Garden & Outdoor which weighs 29 kg but there are lots of different manufacturers to choose from. My 200 Ah battery weighs 58 kg not counting the box it's in which is another 14 kg. In terms of batteries, if it's something you can easily carry around with one hand it probably won't provide all the power you'll need for extended imaging sessions.

Very cool - I've been wondering if both planets in a single frame would be possible. Nice capture!!!

Battery box is now vented to outside.

Termination is screened to prevent insects from entering.

Enclosed on 3 sides to prevent rain from entering.

You should check out this post: 

16 minutes ago, Physopto said:

Once the battery charging voltage passes about 13.6 volts lead acid batteries start to outgas hydrogen.

That is why in the past caravan chargers are set to around 13.6 volts, for safety reasons. Trouble is the batteries are damaged by this irreversibly. The batteries life is very much shortened and capacity is much reduced ! Lead acid needs to get to around 14.4 -14.6 volts for a full charge.

I now use LiFePo4  batteries. But these cannot be charged at or below zero degrees C without  wrecking these type of batteries. Lead acid have no real problems at these temperatures.

I believe the solar charge controller charges my 200 Ah sealed gel battery to 14.1 volts before it goes into float mode which is 13.8 volts. I'm going to re-purpose an extra plastic shop vac hose I found and vent the cooler directly outside which should eliminate any potential build-up of hydrogen gas inside the observatory. I'll post some photos once the vent has been installed.

1 hour ago, Physopto said:

I just have caught up with the last few posts here. I see you were advised to allow a vent in the top of your battery box for ventilation.

It seems that your battery box is inside a building, sealed or not, the battery needs a hydrogen vent to the outside of the building. The vent also needs to be protected by a series of fine filter meshes. I used three meshes sandwiched together in my older setup, I used a waterproof boat vent as the filter holder.

The meshes act as a protection against explosion if the hydrogen gas is exposed to a naked flame, or any kind of spark. As it is at present any escaping hydrogen gas can by the looks of it catch fire and track straight back into the battery box causing a catastrophic explosion and possibly fire or severe injury to yourself or other persons nearby. Remember you have other electronics above the battery box, a possible source of ignition.

Some years ago I had a 110Ah battery explode near me. I was extremely lucky and all that happened was some permanent hearing loss in my left ear and all my clothes were(and me) were covered in Sulphuric Acid. None of my clothes survived but a very quick shower and I was OK. It happened after over twenty years of experience in looking after all sorts of batteries.  One daft slip of concentration was all it took when I was very tired!

The way the meshes work is that they cool the flame front at each mesh. So use three causes three reductions in temperature and no actual flame passing back into the battery box. (Think of how chemists use a filter under a beaker when heating it by a Bunsen gas burner flame.)

Your set up looks great.

Thanks for the warning & think I'll just connect a flexible hose of some sort to the round vent I already installed in top of the cooler and route it directly outside. I thought hydrogen off-gassing was less of an issue with the sealed gel batteries but apparently I was mistaken. Luckily the interface between roof and building is currently unsealed but I'll go ahead & install a vent hoae right away because I obviously don't want any exploding batteries in my nearly completed observatory!

Drilled holes for the cables then sealed the gaps with caulk so the cooler can close. Also, built an overhanging roof to protect the electronics from dew. Had planned to locate the electronic gear in the control pod but was afraid there wouldn’t be enough space left for a desk, laptop and me!

Still need to create openings for the cables so I can close the cooler and also install a couple more circuits but the observatory is now running on its own power instead of a generator.

You would think an M42 male to male adapter would be available from most any online astronomy store but the only one I could find is listed on ebay & ships from China. M42 to M42 42mm - 42mm male-to-male coupling Ring Adapter for Filters 4496849937489 | eBay

I believe the prism position can be adjusted by loosening the knurled set screw shown between your thumb and index finger in photo 2. The prism stem should be long enough to let it project further into the optical path but not so far as to obstruct the light falling on the camera sensor. Support the prism while adjusting so the stem doesn't fall out of its housing.

33 minutes ago, discardedastro said:

Do give it a little bit of ventilation - you don't want hydrogen build-up in your battery box! For really cold weather resistance, a little low-power heater in a reasonably shielded box will go a long way and won't pull much power.

Great advice & I had thought about both those issues. The battery actually states on the side do not charge in a gas-tight container so I'm wondering if just loosening the cooler drain plug or even completely removing it would provide enough ventilation? What type of low-power heater woud you suggest & by "shielded box" do you mean insulated?

1 hour ago, michael8554 said:

Just be aware that the 60D sensor is spring-loaded, so you'll need to measure it's position very accurately, or you'll have a tilted sensor when you reassemble.

Earlier DSLR's before the 500D had sensor tilt adjusted with thin shims, very easy to put those back and preserve the sensor position.

Michael

Of course I would buy a camera that's more difficult to mod but having it done professionally is so darn expensive. You mentioned in your previous post that you're not convinced full spectrum mods are good to do so was wondering why that is. Sounds like you recommend removal of just the Ha filter but that could still cause sensor tilt without precise re-adjustment correct?

33 minutes ago, theropod said:

What good work done here! I’m now inspired to build my own little star shack. If for no other reason than to avoid polar/stellar alignment each and every time I want to use my new eq goto. The ROR set on the ridged rails is so smart. I wonder if a modified garage door opening mechanism could be used to move the roof. Here in Arkansas rain storms can pop up in a matter of minutes, and having a push button powered retraction system seems to make sense.

Thank You! Avoiding the continuous setting up and taking down was my main motivation too but a DIY observatory can get out of control if you're not careful. I've spent way more time and money than I ever planned so glad it's almost done. As far as the garage door opener, it probably depends on the weight of the roof. Mine is likely too heavy for a standard opener and it would use up too much battery power anyway. Therefore I've come up with a low-tech solution - a hook on a pole with several strategically located eye bolts to grab onto 

19 minutes ago, MarsG76 said:

I modded it myself...

I cooled the sensor by cutting to shape and adding a copper plate to the back of the sensor that comes out of the side of the camera. The plate sticking out of the DSLR body has two peltier coolers (with heatsyncs) attached to freeze the copper plate, effectively "sucking" out the heat from the sensor... 

 

My last version cooled the sensor by 18°C below ambience, so I was falling below freezing on nights that were 15°C and initially I did have a problem with dew destroying my main PCB. On subsequent versions I protected the main PCB with hot glue, used some absorption strips inside the DSLR body to fill out the gaps to soak up any moisture from cooling and used expanding foam to fill in around active cooling openings to stop moisture from entering the camera.
 

I added a thin temperature sensor in between the copper plate and the sensor as well as another sensor embedded inside the expanding foam right next to the peltier on the active cooling side to get a accurate reading of the sensor and cooler temperatures. The cooler side dropped to -15°C during the 15°C night. 

At one point the front of the DSLR sensor frosted over so now I wrap a heat strip around the T-Ring/front of the DSLR which stops that... since these condensation protection additions, I did not have a single issue with the DSLR on many nights during the year where the sensor was at 1-2°C (controlled with a temperature controller), usually around 5°C below the dew point... but my subs are virtually noise free and have a much cleaner and crisper look to them.... even the 1800 second subs have almost no noise.

 

 

Wow!!! Very impressive! I'd be nervous just trying to remove the filter and get everything back together without ruining the camera LOL I understand the heatsink but all those tweaks to stop the condensation would be beyond me...