Mandy D

02:39 - Mars quite close to Moon, now.

Tonight's setup for Mars' encounter with our very own Moon is my D800 with a 300 mm prime lens and 2x teleconverter. It was too much effort to lug the scopes out tonight. But, hey, this lens has more aperture and focal length than some refractors!

I'm trying to photograph and post every hour until Mars dissappears behind the Moon. Kipping on the settee in between sessions. That is an interesting shot of your scope pointed at the target. I just took a photo of mine half an hour ago, but haven't posted it.

01:38 - Mars approaching Moon.

00:40, now and the gap is closing.

Mars is scheduled to disappear behind the Moon some time around 05:00 UTC tomorrow as viewed from the UK. It's getting distinctly closer as you can see in my two photos separated by just over an hour, here,

Just over an hour later at 23:40, they are noticably closer.

Mars and the Moon getting closer together, now fit on full-frame sensor of D800 at 600 mm FL.

DSLRs (at least the D800 and presumably all others) use a far bigger chunk of the sensor to capture 1080P video than the pixel count suggests, so do not achieve the same resolution for a given focal length as they do with still images. In other words, you will need to go to greater focal lengths to achieve the desired resolution than you would if you were shooting still frames. D800 is 7360 x 4912 resolution on a full frame, 36 x 24 mm sensor. Video uses 32.8 x 18.4 mm of the sensor, so 6706 x 3766 pixels. This is scaled to 1920 x 1080 at 3.49:1 linear ratio. Hence, you will need to Barlow by a further factor of 3.5 to reach the required f/ratio compared with that for still images. D800 can also film video at reduced resolution of 1280 x 720, but still uses the same 32.8 x 18.4 area of the sensor, hence the ratio is now 5.24:1.

Great answer! Made me smile.

Sorry, not sure what your complaint is. The masking of a corner will positively identify that corner in your image, regardless of optics.

It will depend on the optics in front of the sensor. A simple lens, for example, produces an inverted image. The simplest way to figure out what is happening with your optics and no thinking required is to cover a small piece of one corner of the sensor, take an image and compare.

I was going to post about this one in there, but if I did, could it be topped?

Impressive, indeed! Even though I have a 250mm Newt, I'm certain I could not achieve what you have done here. That's not to say I haven't thought about it, because I have. One day, maybe I'll try. Thank you for sharing your inspiring image with us. 💫

In pink? Hell, yes! Just need some money now ...

I'm liking that! Is that from your observatory or a field trip?

I hate to say it, but (in my opinion) that is exactly what a telescope should not look like! But, on the other hand, probably how Apple would envisage it. Personally I prefer the look of the Pear phone!

No, M10 male will definitely not screw into a 3/8" UNC female thread. It is larger diameter and 1.5 mm pitch against 1.587 mm pitch for 3/8" You could run an M10 tap into the 3/8" thread, but I don't recommend it, especially if it is in aluminium. A length of 3/8" UNC studding (threaded rod) can be purchased, onto which you can screw nuts and handwheels to make something similar to the original M10 fitting on the AZ4. You may have to drill out the threads in the AZ4 tripod head to make this work, but all that means is the rod will not be retained in the tripod when unsscrewed from the head. No biggy.

The other fitting on the large cover is to place the small cap on when it is not covering it's hole. Try it, you will find it is a perfect fit.

I think we have to hold FLO accountable for the extra cloud/fog. It's due to their current sale prices and us all buying more kit with clouds included!

The 8SE is definitely too long to image the whole Moon with a D3100, but you should get some nice crater close-ups. Have a look at this thread by @astrolulu to see what can be achieved with similar focal lengths and apertures. Some of his images are incredible and he is very helpful and approachable. I'm sure I've got a few things wrong with buying equipment, but I don't view it as "wrong", rather as being extra kit that will do another job. Just as long as it is not a big or expensive mistake it is all OK. My RC6 is the "wrong" scope for lunar and planetary imaging, but I love using it for that: It is so much fun and a bit of a challenge. OK, better results can be had with my 200P or 250PX, but sometimes that is not the point. Enjoy the journey!

It is my pleasure to help and glad you found my reply helpful. I had a D3100 as my first DSLR and it was a great little camera, but it got replaced with a D3200 for better resolution (24MP) and then I added a D800 (36MP, full frame). What lens or telescope are you using for the Moon? The crop sensor will be able to capture the full lunar disc with focal lengths up to about 1500 mm, but it is better sticking to less than about 1200 mm as the Moon moves pretty fast through the frame at these focal lengths. It should do a great job on the Moon. I have plans to image the Moon again this week if the clouds clear. Please do share your photos in here, it will be nice to see what you achieve with that camera.

Definitely agree about the old TV sets. Here is a picture of an old radio I picked up on a car boot sale, just because it was pretty. It's a 1945 Sobell model 615 according to the label and internet. Last of the large radios to be produced and it still works. I know it's not a telescope, so I hope it's OK to post. I suppose, you could consider it a radio telescope with a long enough antenna!

The D3100 does support multiple frame continuous shooting mode, but only at a maximum of about 3 fps until the buffer is full, then it will slow down even more. You cannot set it take exposures for a set time period as far as I know and what you need is your "remote shutter thingy" to do this. It has a resolution of 14 MP, which is quite low compared with later cameras, hence it's pixel size of 5 um is large, so to get high resolution on small objects, like the planets you will need extreme focal lengths. For deep sky, it's sensitivity is low, so will need long exposures. Overall it is not a bad camera. It will work great on the Moon.

I think an easy to follow way of looking at this is to consider whether your laser pointer is capable of setting fire to a piece of paper; if not then it should be clear to you that your optics are going to be able to handle it. The second thing is that you are shining the light through the eypiece of the scope, so the beam is going to diverge, hence the energy density of the beam will be lower as it passes through the optical array. Also, remember that refracting telescopes can be used for solar projection and that does involve an awful lot of heat being collected by the telescope, yet it does not melt (usually!). As Wulfrun says, you would need a seriously powerful laser to melt your optics.