Mandy D

@Mr_Cat You do realise that you are measuring the outside diameter of the focuser tube? You need to turn the calipers over and measure the bore., which will come out much closer to 1.25".

I have a large roll of very thin ABS that is covered in dark blue velvet flocking that can be rolled into a 50 mm diameter tube. There is no reason to suppose that it is not available in black.

You most definitely succeded. That is a very nice Uranus.

The link, below, suggests that a 1 mW laser diode draws 20 mA. https://botland.store/laser-diodes/15386-laser-diode-1mw-red-650nm-5v-velleman-wpm434-5410329725501.html So, if you cannot measure the voltage when the battery is in the laser, connect a 150 ohm resistor across the battery and measure the voltage across it with your multimeter. If it falls over time, or drops immediately to low values the battery is no good.

OK, it should have a reasonable apparent brightness at that power and wavelength. Have you checked the battery under load in the laser? Measuring the terminal voltage of a cell off-load indicates nothing. I've seen button cells give the reading you have off-load and fall to practically zero under load. I know you have said it is brand new, but it could be faulty or old stock, still.

The first things I would check is the quoted power output and wavelength. At 670 nm you are approaching the long wavelength limit (700 nm) of human vision. Compare a helium neon (HeNe) laser spot at 0.5 mW and 632.8 nm wavelength with a 670 nm diode at 3 mW. The HeNe will appear much brighter, due not just to improved sensitivity, but it usually produces a tighter collimated spot.

So, after purchasing a 300PDS, I have now gone the opposite way and bought my smallest mirror telescope, yet - a Skymax 90. I looked long and hard for one to use as my travel scope for the eclipse in Fuerteventura and failed, so ended up using a 600 mm lens on my DSLR, instead. Of course, almost as soon as I got back, one came up in here, so I had to buy it! Now, I have clouds.

DSLRs commonly use MOV format. I think it has something to do with file format licencing.

Regular oil based greases as used on cars also tend to be non-conductive, so defeat the object of the excersize. As you suggest, petroleum jelly works very well.

M42, the Orion Nebula is beautiful, readily accessible and easy at this time of year. Obviously, the Moon, but also Jupiter, Saturn and Venus at the moment. Uranus is a bit tougher, but not impossible.

254 nm UV is effective at killing bacteria and microbes. It is commonly referred to as UV-C. It is extremely harmful to human tissue, so zero exposure!!! It is also readily blocked by regular glass (soda glass), but is passed by silica (quartz). My last involvement with it was more than 20 years ago, in connection with pharmaceutical industry, so am very rusty. As you say, it is damaging to plastics.

Looking at a wider field view, it gets even nicer, with Ganymede way off to the left and tiny Amalthea much closer to the planet. I wonder if anyone can capture 5 moons tonight. There is also Thebe at mag 15.47 between Io and Europa, but that is probably a stretch too far!

Yes, the white one comes with and EQ4 mount, whereas the grey one gets only an EQ3 mount.

Take it to an angineering workshop and ask them to helicoil it for you. That will put new steel threads in.

I'm not sure he has, because he specifically states "mount" not platform.

It is certainly an interesting view and I have a bit of blue in my sky this morning. I'll have a look, tonight. Thanks.

@phantomgod_06 what telescope do you have?

I know this will probably not change your mind about the EQ platform, but it is not quite like a regular EQ mount in that it is incapable of tracking for the long periods that a mount is, thus your eyepiece is not going to move very much. Regarding accurate polar alignment, that is only required for long exposure photography. You have already stated that you are happy for the object to drift across your field of view, so a very rough alignment will work.

Yes, absolutely. I often mount mine on a Skytee 2 AZ mount. I've fitted a set of rings and Vixen dovetail to the OTA and it still has the Dobsonian altitude bearings on the tube. It goes back on the Dob base with the rings and dovetail fitted, no problem. See photo:

The handles are designed for carrying them. I do it with my 200P and 250PX. Never had an issue. But, like Beulah says, make sure they are tightened properly.

There is more info in my thread on the tool bag, here: https://stargazerslounge.com/topic/415314-bags-in-space-imaging-challenge/#comment-4431231

Sadly, art is worth far more to most people than science or engineering ever will be!

@astrolulu I've just bought a 90 mm Mak in a similar colour to that one. Yours looks bomb-proof, though. I'm impressed by the folded steel(?) mounting bracket: it looks truly substantial. The whole thing reminds me of 1960s seaside binoculars mounted on a pier into which you had to insert one old penny to use them for two minutes! It is hard to think of you as anything other than a native English speaker when reading your posts, so don't worry about that. Your English is certainly better than my Polish which is limited to tak, sklep, solidarnosk and perastroika and I've probably messed up on the spellings! I will have a read of the article on your blog, later.

Absolutely! 100%. Resolution is all about diameter and as long as you have at least diffraction limited optics, you are simply not going to do better without upgrading the size of the telescope. The only other thing left, once the scope is matched to pixel size, is the skill of the imager and you have that licked!

I had dew form on the inside of a camera lens when I moved my camera equipment in from -24 °C in Switzerland to a warm room. I just put it back in the camera bag and let it come up to room temperature slowly. The next time I looked, a few hours later, it was clear.