<p>Gennady Borisov wrote on <a href="https://astronomy.ru/forum/index.php/topic,175643.0.html" rel="nofollow noreferrer">the astronomy.ru forum</a>:</p>
<blockquote>
<p>The first observations of the object were made in the morning of August 30 with a 650 mm telescope, F / 1.5 Hamilton</p>
</blockquote>
<blockquote>
<p>Первые наблюдения объекта были сделаны под утро 30 августа на телескопе 650 мм, F/1.5 Гамильтоне</p>
</blockquote>
<blockquote>
<p>Yes, this is Hamilton. All surfaces are spheres. Has a 3-lens corrector.
Good image quality, high aperture ratio. Large field of view: on FLI ML16803  FOV:  2.1 х 2.1 deg 1.87&quot;/pixel</p>
</blockquote>
<blockquote>
<p>Да, это Гамильтон. Все поверхности сферы. Имеет 3-х линзовый корректор.
Хорошее качество изображения, высокая светосила. Большое поле зрения: на матрице FLI ML16803  FOV:  2.1 х 2.1 deg 1.87&quot;/pixel
<a href="https://i.sstatic.net/RnRQL.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/RnRQL.jpg" alt="enter image description here" /></a></p>
</blockquote>

CC BY-SA 4.0
2020-11-06T04:05:53.887Z
Thanks for the speedy answer! I'd like to try to read further (with google translate's assistance). I tried searching the page for "Гамильтон" or "гамильтон" or "поверхности" but no success. It's not easy making a 65 cm lens with a big hole in the center; the backstory on how this was done must be interesting! Actually I will ask about how that's done in a separate question so don't answer that here :-)
uhoh
CC BY-SA 4.0
2020-11-06T04:16:27.353Z
[How to make a 65 cm lens with a 20 cm hole in it for a Hamiltonian telescope?](https://astronomy.stackexchange.com/q/39705/7982)
uhoh
CC BY-SA 4.0
2020-11-06T12:13:16.857Z
@uhoh He's not really an amateur. He is an observatory employee who builds and repairs telescopes. The optical system is made on professional equipment.
A. Rumlin
CC BY-SA 4.0
2020-11-06T12:50:41.100Z
Oh I see what you mean, got it. Nonetheless it will be interesting to see how such a "holy lens" (pardon the pun) can be made.
uhoh
CC BY-SA 4.0
2020-11-06T03:02:33.527Z
2020-11-06T12:20:00.687Z
2020-11-06T12:20:00.687Z
A. Rumlin
<p><a href="https://astronomy.stackexchange.com/questions/33337/why-is-this-telescope-so-short-how-hard-is-it-to-make-such-a-fast-primary#comment63049_33347">This comment</a> on the current answer to <em>Why is this telescope so short? How hard is it to make such a fast primary?</em> says</p>
<blockquote>
<p>In this <a href="https://astronomy.ru/forum/index.php/topic,175643.0.html" rel="nofollow noreferrer">forum topic</a> Borisov appears to call it an f/1.5 Hamiltonian.</p>
</blockquote>
<p>Wikipedia's <a href="https://en.wikipedia.org/wiki/Catadioptric_system#Catadioptric_dialytes" rel="nofollow noreferrer">Catadioptric system; Catadioptric dialytes)</a> says:</p>
<blockquote>
<p>Catadioptric dialytes are the earliest type of catadioptric telescope. <strong>They consist of a single-element refracting telescope objective combined with a silver-backed negative lens (similar to a Mangin mirror). The first of these was the Hamiltonian telescope patented by W. F. Hamilton in 1814.</strong> The Schupmann medial telescope designed by German optician Ludwig Schupmann near the end of the 19th century placed the catadioptric mirror beyond the focus of the refractor primary and added a third correcting/focusing lens to the system.</p>
</blockquote>
<p>The image of the telescope in the linked question shows a very short and squat telescope with a 65 cm aperture that does not appear to have a &quot;single-element refracting telescope objective&quot;, so I am confutes!</p>
<p><strong>Questions:</strong></p>
<ol>
<li>What (the heck) is and is not a proper Hamiltonian telescope?</li>
<li>Is the Gennady Borisov telescope in the linked question (and <a href="https://skyandtelescope.org/astronomy-news/possible-interstellar-comet-headed-our-way/" rel="nofollow noreferrer">shown here</a>) one?</li>
</ol>

CC BY-SA 4.0
2020-11-05T22:46:39.487Z
potentially helpful: http://www.ceravolo.com/hamilton.html
uhoh
CC BY-SA 4.0
2020-11-06T02:56:07.313Z
A Hamiltonian telescope is a telescope that visits each vertex of a graph exactly once.
Mark
CC BY-SA 4.0
2020-11-06T05:15:07.127Z
Question: Is this telescope still used today? or has it become obsolete? I think that since it is 19th century technology, it is easily replaced by digital telescopes.
Nilay Ghosh
CC BY-SA 4.0
2020-11-06T09:01:13.173Z
@NilayGhosh according to information [here](https://astronomy.stackexchange.com/q/33337/7982) and in the answer below, Gennady Borisov discovered comet G Borisov in 2019 with one, so I would say yes, it is still being used!
uhoh
<telescope><amateur-observing><history><optics><terminology>
What exactly is a Hamiltonian telescope? Is this one?
uhoh
# What exactly is a Hamiltonian telescope? Is this one?

(Asked by: username_0 on 2020-11-05)

[This comment](https://astronomy.stackexchange.com/questions/33337/why-is-this-telescope-so-short-how-hard-is-it-to-make-such-a-fast-primary#comment63049_33347) on the current answer to *Why is this telescope so short? How hard is it to make such a fast primary?* says

> In this [forum topic](https://astronomy.ru/forum/index.php/topic,175643.0.html) Borisov appears to call it an f/1.5 Hamiltonian.

Wikipedia's [Catadioptric system; Catadioptric dialytes)](https://en.wikipedia.org/wiki/Catadioptric_system#Catadioptric_dialytes) says:

> Catadioptric dialytes are the earliest type of catadioptric telescope. **They consist of a single-element refracting telescope objective combined with a silver-backed negative lens (similar to a Mangin mirror). The first of these was the Hamiltonian telescope patented by W. F. Hamilton in 1814.** The Schupmann medial telescope designed by German optician Ludwig Schupmann near the end of the 19th century placed the catadioptric mirror beyond the focus of the refractor primary and added a third correcting/focusing lens to the system.

The image of the telescope in the linked question shows a very short and squat telescope with a 65 cm aperture that does not appear to have a "single-element refracting telescope objective", so I am confutes!

**Questions:**

1. What (the heck) is and is not a proper Hamiltonian telescope?
2. Is the Gennady Borisov telescope in the linked question (and [shown here](https://skyandtelescope.org/astronomy-news/possible-interstellar-comet-headed-our-way/)) one?

**Tags:** telescope, amateur-observing, history, optics, terminology
> **Comments:**
> **username_0**: potentially helpful: http://www.ceravolo.com/hamilton.html  
> **username_1**: A Hamiltonian telescope is a telescope that visits each vertex of a graph exactly once.  
> **username_2**: Question: Is this telescope still used today? or has it become obsolete? I think that since it is 19th century technology, it is easily replaced by digital telescopes.  
> **username_0**: @NilayGhosh according to information [here](https://astronomy.stackexchange.com/q/33337/7982) and in the answer below, Gennady Borisov discovered comet G Borisov in 2019 with one, so I would say yes, it is still being used!  

---

## 1 answers

### Answer by username_3 on 2020-11-06. Score: 3 | Accepted answer

Gennady Borisov wrote on [the astronomy.ru forum](https://astronomy.ru/forum/index.php/topic,175643.0.html):

> The first observations of the object were made in the morning of August 30 with a 650 mm telescope, F / 1.5 Hamilton

> Первые наблюдения объекта были сделаны под утро 30 августа на телескопе 650 мм, F/1.5 Гамильтоне

> Yes, this is Hamilton. All surfaces are spheres. Has a 3-lens corrector.
> Good image quality, high aperture ratio. Large field of view: on FLI ML16803 FOV: 2.1 х 2.1 deg 1.87"/pixel

> Да, это Гамильтон. Все поверхности сферы. Имеет 3-х линзовый корректор.
> Хорошее качество изображения, высокая светосила. Большое поле зрения: на матрице FLI ML16803 FOV: 2.1 х 2.1 deg 1.87"/pixel
> [![enter image description here](https://i.sstatic.net/RnRQL.jpg)](https://i.sstatic.net/RnRQL.jpg)

> **Comments:**
> **username_0**: Thanks for the speedy answer! I'd like to try to read further (with google translate's assistance). I tried searching the page for "Гамильтон" or "гамильтон" or "поверхности" but no success. It's not easy making a 65 cm lens with a big hole in the center; the backstory on how this was done must be interesting! Actually I will ask about how that's done in a separate question so don't answer that here :-)  
> **username_0**: [How to make a 65 cm lens with a 20 cm hole in it for a Hamiltonian telescope?](https://astronomy.stackexchange.com/q/39705/7982)  
> **username_3**: @uhoh He's not really an amateur. He is an observatory employee who builds and repairs telescopes. The optical system is made on professional equipment.  
> **username_0**: Oh I see what you mean, got it. Nonetheless it will be interesting to see how such a "holy lens" (pardon the pun) can be made.  

---

