dannybgoode

Now that’s a nice M42. I am going to face another crack at it this year. Was my first target when starting out last year and ended up with a passable image but not a tenth of this one. A level to aspire to

Just looked through pretty much this while thread. There’s some beautiful scopes in here! I only own one frac and I’ve shared pictures of it before but may as well post it here for posterity. First and only frac - my TMP Optical 105/650 CNC. Original batch, Thomas Back made. Works great for visual and imaging. I was thinking about a shorter frac for wide field but may just get the 0.75 Riccardi reducer/flattener. Shouldn’t have bought it but hey-what money for years of pleasure?

You’re certainly right about the advantages of a 6” newt. I have the f5 SW 150P and really like it. Large enough aperture to be useful, small enough to be manageable. You’re also right about the potential issues of an f5 although I notice them more when I try to image with mine rather than visual. An f6 is indeed an interesting proposition. If you do bite the bullet let me know what it’s like.

@Tzetze - thanks for the information. I haven’t delved into the murky world of Pixinsight but I’m going to investigate it

Lovely image - a level of quality to aspire to Quick question - how do you rescale the L shot 1x1 and the RGB shot 2x2. Do you resize the L accordingly or is there another method?

This is interesting stuff and my apologies for confusing the terms. A little knowledge and am that @vlaiv and others - are there any good primers/books on the more advanced and technical aspects of AP; the subject of SNR, well depth, gain iro of CMOS etc? I have pretty much got to grips with the ‘physical’ side of AP; actually getting there whole thing set up and imaging and am keen to gain a better grounding in the technical theory behind it all.

Nice image. Much better than the beat M42 I’ve managed. Only tip I’d give is to take some shorter exposure frames to blend and try and tackle the core so it’s not so blown out.

The focal ratio determines whether it is a fast or slow scope and is calculated by dividing the focal length but the aperture. So my refractor has a focal length of 650mm and an aperture of 105mm so it’s focal ratio is f6.2 and is a moderately fast scope. My Skywatcher Newtonian has a focal length of 750mm and an aperture of 150mm so has a focal ratio of f5 and is moving toward the realms of fast. My Meade 10” SCT has a focal length of 2500mm and an aperture of 250mm so has a focal length of 250mm so has a focal ratio of f10 so is a slower scope. Note of my three scopes the one with the longest focal length is the slowest. For visual observations the focal ratio doesn’t particularly matter. For astrophotography, a scope with a focal ratio of f5 will collect light twice as quickly as a scope of f10. So, you could take subs of say 3 minutes instead of 6. The focal length though has an impact of field of view in respect of astrophotography and magnification in respect of visual. The magnification of a scope is calculated by focal length of scope/focal length of eye piece. So to achieve a magnification of 250x on my 10” SCT I only need a 10mm eyepiece but of my 105mm I would need a 2.6mm or so. Short focal eyepiece are expensive to make, especially to achieve high image quality, 10mm ones not so much. Again for my Meade I can use my 2” 24mm and have lovely wide field 100x mag views that are pin sharp and with nice long eye relief.

Thanks again @vlaiv Would I be right in thinking then that binning can be useful to prevent oversampling (or undersampling - I can’t quite get my head around which!) with long focal length scopes? So for example using my SX674 mono with my TMB 105/650 gives me a result of 1.43” pp so about right. However if I wanted to use my Meade 10” SCT with an FL 2500 then binning 2x gives me 0.74 or using my f6.3 flattener/reducer 1.18 so just about spot on?

Thanks @vlaiv - that’s the chestnut I was looking for. Am I right in thinking that it is pixel size in um (apologies on the phone so can’t get the proper character!). So if my pixel size is 4.5 um then I just use 4.5?

Quick one this - can someone remind me of the formula for calculating a scope/ camera saving resolution please? Someone posted it a while ago on another thread but I just can’t find it. Thanks all

Oh thanks for that link - some superb images and charts. That’s the desktop picture on my work computer sorted for a while I generally use the Moon Globe app when at the scope and have a small Collins or Phillips one by would love a really good atlas for studying indoors.

Thanks all For the money I think I’ll wait. At this phase of the moon my house and trees block it anyway so no hurry until after Christmas and will stick to the plan to get a Delos or Pentax XW. @John I have a mid-vintage Meade 10” SCT OTA which is excellent but I have often read of people having issues with their mounts and electronics.

So in my quest for a good 10mm I have come across an early secondhand Meade 9.7mm 4000 Super Plossl. Japanese optics and in mint condition - worth a look?

I have bought a motley selection of makes depending on the budget I had at the time but have always tried to spend more on shorter FL’s as generally they require the better optics in order to make the most of the higher magnifications they offer. I particularly like my two Explore Scientific MaxVisions. I have a 16mm 1.25” and 24mm 2”, the latter in particular giving really sharp wide views. My Vixen 2.4mm planetary is also a killer but needs a decent scope to get the most out of it. I am quite happy searching out secondhand bargains as well as the ‘giant killers’. My 12mm BST gets a lot of use for example. Basically I decide on what FL I want then find a good EP in that range. Make and model are secondary

Anyone have any experience with this little mount. Looks ideal for something like my Ricoh GRIII for widefield work. Well priced too but of course if it’s rubbish it doesn’t matter how cheap it is. https://www.moveshootmove.com/?aff=2

Very true however Adobe has a long history of yearly or biannual major updates so the model has always been a bit different. I do need to try PI tough to determine whether I can get on with it. I have the book just not the software Anyway I’m at risk of derailing this thread so I’ll shut up now To the OP - get a really good mount next and everything else can follow...

Until you have to pay for the next version of course. I can see both sides to the argument subscription licenses but given how expensive PS CS was I worked out that assuming you always kept it up to date and assuming you bought a legit copy of PS and LR it’s take many years of subs until it started costing you more. Of course if you choose not to update your software with each release this doesn’t hold so true but with PS CS costing somewhere around £650 and LR another £100 or so you’re still looking at 6 years of subs before it cost you more to subscribe. And I don’t have £750 up front for software so it actually suits me just fine. Am currently trying to decide whether to go APP or PI for my initial data processing but PS is a useful tool in the armoury. But then I do a lot of terrestrial photography too

Quick note on Photoshop - you can get the photographer subscription which gives you full Photoshop and Lightroom for £10 p/m. Well worth the asking price imo. As for your £700. Save it until you can afford an SW AZ EQ6 GT. Brilliant mount imo and will survive future scope upgrades. The mount is king but may as well put toward a serious upgrade.

The Series 4 is probably the better buy and can be found quite a lot cheaper. Internally the same but the S5 has the always on screen (which just saps the battery) and a compass. The S4 is the way to go

According to the spec on the FLO the carrying capacity is even higher with a counter weight fitted. I too would be interested in some user feedback. Way out of budget at the moment but makes a very interesting proposition for a true portable AP rig that’s not limited in what scopes it can handle.

Don’t know if anyone wise has spotted these but Apple have added 3 ‘Astronomy’ faces to the watch gallery. The Earth view darkened and lightens with the current time, the moon one shows the current phase and my favourite, the orrery, shows the position of the planets. Rather neatly though turning the crown moves the date forward and backward and in the case of the moon phase shows the phase on any given date and on the orrery, the position of the planets. Hence for example I can see that the opposition of Jupiter will be mid-July.

Sorry mate. Forgot about this. Knew I’d posted the photos on here somewhere. Excuse the technical quality - was stood in the garden in my underwear and didn’t want to alarm the neighbours by loitering too long. Was this something like what you saw?

As per @John’s post the theoretical maximum isn’t always useful. You’ll often find that you can see more at slightly lower powers as the view is sharper and has more contrast. Best analogy I can give is when you look at a photo on screen, let’s say of a bird. The bird is a little small but very clear and you can see a lot of detail so you decide to zoom in. But zooming in makes the bird a bit fuzzy. Sure it’s bigger but the definition is lost as is the detail. One of the first lessons of astronomy is that often less is more

Supreme photos. Truly stunning.