Vroobel

Hi everyone, 

I began my adventure with longer scopes (and my first refractors) totally accidentally thanks to @Franklin, who sold me his Vixen A80M Japan (F/11.4) in June this year. It is wonderful achromatic refractor allowing me to see even 4 biggest craterlets of the Plato with negligible CA, while the seeing was average. Less than three months later I bought a new Starwave Ascent 102ED F/11, which is just enough for me at this moment. They are only two, but the two make a collection now.

I'm preparing to test of general performance and comparison of both thanks to doubled every eyepiece, as I use binoviewer. This is how I'll do the live comparison:

The 102ED doesn't have extended dew shield, so it looks similar to the Vixen, but it's much longer.

I'll add pictures of single slopes soon. 

Absolutely impressive! 😍

Thanks!

I consider creating a home F/11 club 😊

Thanks, but I want it there. I aim today in 249x and 321x magnification. But seeing is poor tonight and clouds are passing. 😕

It is, indeed! Look please at the star test Out and In. 😳

Hi everyone! 🙂

Tonight my brand new Altair ASCENT 102ED/1122 F/11 gets its first light. Some optical test, including the start test, shows that it's really Planet Killer. Let's check by looking at Jupiter and Moon tonight using Japanese Genuine Abbe Orthos 9mm (249x) and Fujiyama HD Orthos 7mm (321x). 😎

17 hours ago, Roy Challen said:

In fact, I wonder why they are winged in one direction only, it would be better if they extended both ways, although not as far in one direction as the other.

Do you mean something like in the picture? Or like egg chair? My eyecup has 2mm collar over 1mm diaphragm to allow eyeball go into the eyecup slightly. Eyebrow, nose and cheek protect 3 other directions from the side light. For me it's very comfortable and working well. 

17 hours ago, Zeta Reticulan said:

Eyecups for ortho's, whatever next?

I've no idea. Falcon 10? 😏

I'd be happy to know an exact outer diameter of other Orthos'. I think they are the same 34mm (33.95).

Great idea about the bicycle inner tube! I like it!

Hi,

Recently I purchased Ortho EPs manufactured by Masuyama to use with my A80M and binoviewer. They have 33.95mm diameter. I think a winged eyecup designed by me will also match Fujiyama, Kasai, Antares and other Japanese Orthos. If not, you can adjust a Horizontal Expansion (which I set as -0.25) or simply stretch it in Cura or other slicer. A vertical stretch is also possible. All details are provided on the project website:

https://www.thingiverse.com/thing:5492218

It may be important that some factory made eyecups may cost 14$... 

Oh, I'm sorry for so late reply.

The Halfords writes: The Yuasa U1R Specialist and Garden Battery is designed for ride on mowers, kit cars, garden tractors and specialist applications. Its rugged construction resists vibration and deep discharge damage,the L-type terminal allows quick and easy installation. This battery is supplied charged and ready to fit, it is fully maintenance free with advanced safety features.

So I hope, I can easily work till the voltage doesn't drop below 12V. The voltmeter, which I used, has buzzer set on the 12V threshold. But my experience says that once fully charged I can play 2-3 nights, depending on the heating need. The stepper motor used for the moto focuser get's the Enable state switched off 1sec after its use, so the power consumption is really minimal.

Hi guys,

Thank you all for very interesting thread. Orginally I wanted to buy the ASI533MC, but I'm not sure now.

I have Bresser Messier 254 Newtonian: 10", 1270mm, F/5 cut to 9" F/5.5 because of not nice shadow of the main mirror holders and focuser tube. Doesn't matter, 230mm is still a big diameter. Now I use EOS 6D with Baader MPCC Mk III and it works well. I have pic scale 1.06 "/px. I have also SW Evoguide 50 ED + FF with 3.2 "/px scale. Their ratio is 1:3.01 and I am happy with that. 

You may think how I swing the 17kg OTA, around 20kg with all accessories? I have 100% ATM heavy fork mount, 70+ kg load capacity. Its accuracy is now around 0.1-0.2", as I use stepper motors without encoders. My best RMS was 1.2"/px, but the seeing was around 2.4" (according the meteoblue). I expect it to be much better, when the seeing allows. Recently I wait...

Well, regarding the ASI533MC, I thought I want it, as I aim in small DSOs. Presenly I have 1.06"/px scale, but with the 533 I should have 0.61"/px that is not too good. I don't want to pay £1k and stuck with the lucky imaging, what do you think? 

Adam J , exactly two years ago you wrote "don't touch the ATIK414XE OSC", why? I finally smiled for a while, because it would give me 1.05"/px that is exactly same as my EOS 6, but it has smaller smensor, additionally cooled! Look, how huge is the M13 in my setup with that ATIK! I know that I can get the same size by cropping pics from the EOS 6D, but I cannot get the cooling this way. Moreover, I think I wouldn't need the CC with that!

I want exactly the OSC, because I live in Liverpool and I have no good weather and not enough time for spending it playing with mono and filters. I have Optolong L-eXtreme and IDAS LPS-D2 and they must be enough for now. 

So, why not the ATIK414XE OSC?

Thanks in advance for expanding this subject.

Tomasz.

11 hours ago, ONIKKINEN said:

Some urban planetary work with saturn in view.

Seeing is not half bad visually. Lets see if that translates to an image...

Thankfully it's not a DS astrophotography, the lights around are not working too bad for planets. 

Dream Team

Finally my heavy ATM fork mount in action. All, excluding the 10" Bresser OTA, made from scratch at home/garden. A big harmonic drive is a heart of the mount. 70+ kg load capacity. 😁 The OnStep firmware @ FYSETC S6 board and the Astroberry @ Raspberry Pi 4 8GB do the job for me. It's not easy, but now I have 0.1 arcsec precision. Yesterday I checked its 1270mm focal length with the M57 and L-eXtreme, tonight I'm going to beat it with 2x Barlow ED. Canon 6D, Baader MPCC III and IDAS LPS-D2. 

Fingers crossed... 🤞

Hi

The controller is finished now and I can share some facts and pictures.

As you can see, that's a form of hat for a small 12V 30Ah rechargeable battery, like half the size of one for a petrol car. All design is made in a FreeCAD, I like this program, it's free and not too hard. This construction allows easy disconnection for charging. Once fully charged battery allows at least 3 nights of fun. It should be very cold and wet at night and I should use 4 heaters fully driven to significantly limit the time. The goal of reasonable mobility (using car) is obtained.

Power switch, 4x20 chars LCD, encoder with micro switch and digital voltmeter including buzzer informing about drop of the voltage below individually set level. The 12V voltage provides excess over the need, as the Arduino drives 4 MOSFET transistors using pulse width modulation (PWM), so 9V or even 7V should be enough to drive the heaters. I don't know yet the efficiency of the set, when the voltage drops so much.

The encoder is a great thing, rotation with explicit jumps allows to precisely increase or decrease the setting of deltaT over the dew point. The minimum reasonable setting is +6°C, but I let it change up to +20°C. Pressing the axis of the encoder I change an active channel, so I can set a different temperature for each heater. One picture below shows the selected channel by asterisk (*), while the value of deltaT is also displayed for the exact heater. The picture shows 3 heaters at work with settings 1:+10°C, 2:+15°C, 3:+20°C. The fourth channel is not occupied now. Why did I decide to be able to set different temperatures? Recently I checked it in practice, the lens of my Vixen A80M was fine with +6°C over the dew point, while BST eyepieces in the binoviewer were getting foggy because of extra humidity from my eyes!  I had to increase the deltaT significantly (I don't remember, 15-20°C) to remove the dew, but in the meantime I heated up the air over the lens. 

Two USB sockets provide 5.1V power for the purpose of the RA drive in my EQ5 mount. Two aviation GX sockets are there for remote control and stepper motor of home made moto-focuser (another story, but the same Arduino and the same battery work for it). I like the GX connectors for their variety and stability. There is also an Adafruit BME280 weather sensor in front (instead the DHT22 mentioned in previous post, I changed mind) and a USB extension for the Arduino, so I don't need to open the box to improve my code.

The code supports possibly every variant and order of connection and disconnection of the heaters and NTC sensors. This is against accidental tearing the cables out or if I forget to connect something and decide to do it later. The sensors are placed inside of heating bands. It's good to know that the NTC thermistors, which I used, has reversed characteristics, so if the circuit is open, the PID algorithm takes it as very high resistance that means low temperature and it strives to heat the heater up (https://www.sensortips.com/featured/what-is-the-difference-between-an-ntc-and-a-ptc-thermistor/#:~:text=Both negative temperature coefficient (NTC,allows current to pass through). The PID_v2 library is quite universal, but I didn't have more time to dig in it.

I'd like to mention that the case is designed in a way to run the dew down, so it's safe.

What can it do?
- readout of an ambient temperature, relative humidity (and pressure of the air, if needed),
- calculation of the dew point,
- driving independently 4 channels using PID and PWM,
- allowing of independent setting of temperature for each channel between 6 and 20 °C,
- measurement of the battery voltage with informing (buzzer) about dangerous drop of the voltage,
- providing 2 x USB power,
- steering of moto-focuser based on LV8729 driver (or any in Pololu standard) and Nema 14 stepper with 5:1 planetary gearbox.

The gadget was recently tested in its initial version during my first hunt for the planets, but I added some features, so I cannot wait for a clear sky now. 

BTW, regarding the additional drop of voltage on wires of the NTC, I took it into account and I think that the total resistance of the NTC and its wires is measured in the readout. I think I shouldn't care too much as the PID watches the process and heaters do the job. Let's check ASAP!  

Hi, 

Tonight I began my first hunting for the planets with Vixen A80M. 😊 Saturn and Jupiter sorted, I still wait for Mars. 

Hi all, 

Recently I bought a quite nice Vixen A80M, and now equipped with driven EQ5, quality diagonal, OVL bino and some pairs of EPs I would say I'm ready to watch the Moon, planets, doubles, etc. But I cannot... 

I'm not sure a rest of the UK, but Liverpool is very moody in terms of weather. Since the New Year I had literally 6-7 good nights. But even if the weather seems good, the dew kills the fun.

So I decided to build a 4-channel Arduino based smart dew heaters controller with DHT22 and NTC thermistors. Additionally I'm going to join a feature of the dew heaters controller with a moto-focuser controller, which is already working (as prototype). I use the Arduino Nano, so I have limited number of IOs. I have a plan to use a higher capacity rechargeable battery, because I want to make the refractor totally portable. A case for the multi-function controller will be 3D printed. 

My idea is to keep constant difference between a temperature of the heaters and an ambient temperature and I can easily do it using a PID_v2 library and some NTC theory. That works very well and I can control the difference of temperatures by potentiometer in range 0-20*C. 

I have two questions at this moment:

1. Is it really reasonable to base the algorithm on a dew point instead of my current solution? Or maybe I can switch the controller between the two options if/when needed? I know, how to calculate the dew point, but how the controller should work based on that? 

2. How big the difference between temperatures of heaters and ambient should be? As I wrote, I can set it between 0 and 20*C now, but I can expect that too small difference is not sufficient while too big difference causes heating air over lenses affecting seeing. What is your experience in this matter? 

I found that some people don't need to use heaters with EPs, but in Liverpool I experienced the dew on EPs many times. 

BTW, today I found this project:

Accidentally we had similar ideas, but my controller won't be so high-end. Despite this, if someone is interested in copying my simpler ideas I'll share them. 

Thanks for any support 

Tomasz

8 hours ago, Captain Scarlet said:

Well, actually, yes! We might even be able to stretch to a room 😀! 1.5 hours drive W from Cork airport, car hire remarkably inexpensive. And that applies to mostly anyone on here as I’ve worked out that we on SGL are a friendly often nerdy bunch!

Like of cats essential though 🐈 

Wow, I know that sky! My friends lived in Thomastown, in a half way between Cork and Dublin. I was so hugely impressed how many stars I could see... ✨ ⭐ 😍

Now they moved elsewhere and didn't take the sky with them... 😒

Tomasz

It is, indeed! I'm gonna equip it with a bino, then the impression will increase.

Thanks

910mm, it's F/11.4. 

Hi, 

I'm pleased to show another Vixen in action: A80M Japan. Unfortunately not at night, it's during observing the Sun. I've bought it from our fellow on SGL recently.

Very clever laptop stand
OK, I like your pier as well

I will do it as soon as I am ready to go, but not yet. Thanks again.

Thank you, I appretiate it as well.

Is the permission given to all astronomers amateurs, or personally to you?