Deadlake

What about diagonal and EP. 3” explorer scientific and 30 mm EP versus greater then 44 mm aperture 2” and 41 m panopticon or 40mm paragon. How would image size the scope could illuminate effect this?

A newt would work, question around size of central obstruction. Boren-Simon powernewts are rated for this, as would the usual suspects found here: https://www.teleskop-express.de/shop/index.php/cat/c58_Telescopes-with-field-corrector.html

we only really needed this line to answer this.... Televue 127mm/ F 5.5 LZOS 130mm/ F6 Sharpstar 121 DQ / F5.5 I can think of, none are cheap.

I’d say yes for the DOB. Also large imaging circle as well, as discussed in article.

@FLO Ignoring border issues, are prices of Europe sourced items going to increase, e.g. Baader for instance?

The free lunch of lower prices from China could never last. If transport costs did fall, I suspect cost of living rising in China will make up the difference. The new normal.

Interesting read John, this part t is important that the telescope used gives good star images out to the edge of the field and for a Newtonian a coma corrector such as the Baader MkIII MPCC would be required whilst for a refractor a field flattener such as the Teleskop Service 2-inch TSFLAT2 should be used. Very few telescopes will give a sharp flat field over that encompassed by the Explore Scientific 30 mm eyepiece and these would be termed astrographs – but few of these have image circles greater than ~44 mm. Is Prof Morrison suggested to get the richest view, you should consider using a fast scope that’s has a field flatterer and a minimal image circle of 44mm. It’s not just a fast telescope that is required, it’s an Astrograph?

Any reason why, you think humidity will compromise the scope?

A filter wheel, no more fumbling around with filters in the cold night. Always fun making sure they don't drop out. Also bit more back focus for larger EPs.

I’m tempted too, but more around the time taken to setup each night. Just going out and powering it up is more attractive. Out of interest if you have an observatory why limit yourself to a 4”?

What about a dome observatory, better than a roll off? How much protection dies a dome give against breathing cold air???

So how cold does it have to be before you have to consider this, presume function of humidity as well. Number of ponds and streams around where I live as well. Is @mikeDnight red light test is as good as any to see if there is water present? I can feel moisture on the tube when I take my refactor in, so guess that implies there is a enough water around to cause issues if not allowed to evaporate. Hopefully will not have cold nights like this for some time, doesn’t seem to improve the seeing which is not what I expected.

You could step up to a TSA 102 and no one would notice in the immediate vicinity....😃😄😊

You could start a thread somewhere title "Is the TSA102S the best 4" telescope ever". Free advertising..... 😀

Hm make a nice replacement for my Vixen, might even get to my house before my LZOS turns up. I'm sure it will be snapped up. @JeremyS is above his Tak allowance. 😀

I get surprised thats classified as Bortle 4. family live near Brecon Beacons and thats Bortle 3, say > 21.5 SQM.

What bred of dog have you got?

The Bortle scale is a little losely defined, so I can see why you don't find it precise. A large range of SQM is covered each scale in the Bortle system. Hence the interest in NV, I'd like to see Nebulae better, only possible using filters. Also I find SQM directional, towards London I don't really look as the sky as effected by light pollution. Below is close, but also quite a wide description. the zodiacal light is still visible, but does not extend halfway to the zenith at dusk or dawn light pollution domes visible in several directions clouds are illuminated in the directions of the light sources, dark overhead surroundings are clearly visible, even at a distance the Milky Way well above the horizon is still impressive, but lacks detail M33 is a difficult averted vision object, only visible when high in the sky limiting magnitude with 12.5" reflector is 15.5 M33 needs a scope where I live.....

Fair enough, in my garden around 20.5 SQM using Dark Sky Meter. I should measure some more to see how it varies.

How dark is it where you live, I have just Bortle 4 skies.

Ever tried to see a report on these: https://www.astronomik.com/en/infrarot-passfilter-infrared-pass-filters/proplanet-807-filter.html meant to help out with planets when poor seeing, however that could start another thread. 😃

DaRk Skies, how dark. Less then or equal to Bortle 3?

I have those too, in fact compared with other filters relatively inexpensive. Not had any others to compare with.

yes, the Baader are on the list.

I modify the amount o polarisation of the filter. Allows details to pop out, rather than hidden under glare. A binoviewer is on my list, not cheap going on these forums...